https://script.spoken-tutorial.org/api.php?action=feedcontributions&feedformat=atom&user=Anjana 2026-04-18T01:14:19Z User contributions MediaWiki 1.23.17 https://script.spoken-tutorial.org/index.php/Ruby/C3/Object-Oriented-Programming-Methods/English 2014-12-22T08:38:25Z

<p>Anjana: </p> <hr /> <div>'''Title of script: Object Oriented concept in Ruby'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> <br /> '''Keywords: class'''<br /> <br /> <br /> <br /> {| style=&quot;border-spacing:0;&quot;<br /> | style=&quot;border-top:0.05pt solid #000000;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| '''Visual Cue'''<br /> | style=&quot;border:0.05pt solid #000000;padding:0.097cm;&quot;| '''Narration'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 1<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Welcome to this spoken tutorial on '''Object Oriented Programming – Methods '''in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 2<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| In this tutorial we will learn to use:<br /> <br /> * '''instance methods'''<br /> * '''class methods'''<br /> * '''accessor methods'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 3<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here we are using<br /> <br /> * '''Ubuntu '''version 12.04<br /> * '''Ruby'''1.9.3<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 4<br /> <br /> Pre-requisites<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| To follow this tutorial, you must have a working '''Internet '''Connection.<br /> <br /> <br /> You must also have knowledge of '''Linux '''commands, '''Terminal '''and '''Text-editor.'''<br /> <br /> <br /> If not, for relevant tutorials, please visit our website.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Before we begin, recall that we had created “'''ttt'''” directory earlier.<br /> <br /> <br /> Let's go to that directory.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the '''terminal''' which has all the commands for creating the directories and the prompt should be in '''oop-methods '''directory<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then to '''ruby-tutorial.'''<br /> <br /> '''Create a directory names''' '''oop-methods and cd into it'''.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 5 <br /> <br /> What are '''instance''' '''methods'''?<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| What are '''Instance methods'''?<br /> <br /> <br /> '''Instance methods '''are those '''methods '''that are available to all '''instances '''of the '''class.'''<br /> <br /> <br /> Earlier we had studied how to create '''objects '''or '''instances '''of a''' class'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit''' where you have already opened the file '''“instance_methods.rb” '''with the class defnition''' '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''instance_methods.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of the implementing '''instance methods'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the “'''initialize'''” method block<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a '''class '''named '''Product''' in this example.<br /> <br /> <br /> I have called an '''initialize''' '''method '''to initialize the '''instance variables''' “'''name'''” and “'''price'''”.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the methods “'''name'''” and “'''price'''”<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have also defined '''instance methods '''named “'''name'''” and “'''price'''”.<br /> <br /> <br /> Each of them return '''instance variables''' '''“@name'''” and '''“@price'''” respectively.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Instance methods '''are defined just like normal '''methods'''.<br /> <br /> <br /> Earlier we had studied how to create '''methods '''in '''Ruby'''.<br /> <br /> <br /> Shortly we will see how these '''methods '''will be available to all '''instances.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us implement the logic we have.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the poduct object creation code.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here, I have initialized a '''Product''' '''object '''and named it as '''product_object_1'''.<br /> <br /> <br /> I have initialized it with a name Added. Pls validate.value and a price Added. Pls validate.value.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''initialize''' block.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| The '''initializer block''' passes the values to the '''instance variables''' '''@name''' and '''@price'''.<br /> <br /> <br /> Earlier we had studied about '''instance''' '''variables'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight''' :'''<br /> <br /> '''puts product_object_1.name '''<br /> <br /> '''puts product_object_1.price'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now this '''product instance '''or '''object''' can use the''' instance methods''' '''name''' and '''price'''.<br /> <br /> <br /> On invoking these '''methods,''' we get the values stored in the '''instance variables'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type-<br /> <br /> '''ruby instance_methods.rb &gt;&gt; '''press '''Enter'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us execute this code.<br /> <br /> <br /> Switch to the '''terminal''' and type:<br /> <br /> '''ruby instance_methods.rb '''<br /> <br /> <br /> and press '''Enter '''to see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Point to the output.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will see that it will print the values you initialized the '''object''' with.<br /> <br /> <br /> Added. Pls validate.Namely, '''laptop '''and '''35,000'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us switch back to '''gedit'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the initialization of '''product_object_2'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us initialize another '''instance''' or '''object'''.<br /> <br /> <br /> Let us name this object '''product_object_2'''.<br /> <br /> <br /> This time let us give a different set of values for name and price.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''puts '''statements<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us call the '''instance methods '''“'''name'''” and “'''price'''” for this '''object.'''<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the '''terminal '''&gt;&gt; Press up-arrow &gt;&gt; '''Enter.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us switch back to the terminal and execute the code like before.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Output on the '''terminal.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice that it executes successfully and prints out the new values.<br /> <br /> <br /> This proves that '''instance methods''' are available to all '''objects''' of the '''class Product'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You should now be able to write your own '''instance methods.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us look at what '''class methods '''are.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 6<br /> <br /> What are '''class''' '''methods'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Class''' '''methods''' are '''methods '''available only to the '''class.'''<br /> <br /> <br /> These '''methods '''are not available to instances of the '''class.'''<br /> <br /> There are different ways you can define class methods.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us look at an example.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit''' where you have already opened the file '''“class_methods.rb” '''with the class defnition''' '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''class_methods.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of '''class methods'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''Product.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a '''Product''' '''class''' like before.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''initialize''' code block.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have also called an initializer like before.<br /> <br /> <br /> However, this time I have added an extra '''argument''' called '''description'''.<br /> <br /> I am also using class variables to hold the values unlike instance variables earlier.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the first class declaration code.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| This '''class''' will demonstrate to you the 3 different ways one can define '''class methods.'''<br /> <br /> <br /> Checkout the '''class method '''declaration for '''name'''.<br /> <br /> <br /> Here it is defined using the '''class name Product'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the second class declaration code.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then checkout the second '''class methods''' declaration.<br /> <br /> <br /> Here I have used the '''self''' '''keyword'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the second class declaration code.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next, checkout the third way you can define '''class methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us implement these '''class''' '''methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the object creation logic.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us first initialize an object of '''Product''' like before.<br /> <br /> <br /> This time we are also giving a value for the '''description'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the lines corresponding the class method invocation.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us invoke the '''class''' '''methods''' as shown here.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I did not get any output on executing this file.<br /> <br /> <br /> Pls check the code.Now let us execute the code and inspect the output.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the '''terminal '''&gt;&gt; type '''ruby class_methods.rb''' &gt;&gt; '''Enter.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the terminal and execute the code like before.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Output on the '''terminal.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice that it will print the values for '''name, price '''and''' description.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now you should be able to write your own class methods.<br /> <br /> <br /> &lt;nowiki&gt;&lt;&lt;PAUSE&gt;&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next we shall see what '''accessor methods''' are.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 5<br /> <br /> What are '''accessor''' '''methods'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Ruby''' uses '''accessor''' '''methods''' to access data defined within '''classes'''.<br /> <br /> <br /> Accessor methods comprise of '''setter methods''' and '''getter methods'''.<br /> <br /> <br /> '''Setter methods''' set the values.<br /> <br /> <br /> '''Getter methods''' get those values.<br /> <br /> <br /> '''Ruby''' uses the '''keyword''' '''attr_accessor''' to declare these '''methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us look at an example of '''accessor methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit''' where you have already opened the file '''“accessor_methods.rb” '''with the class defnition''' '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''accessor_methods.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of the implementing '''accessor methods'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “'''attr_accessor'''” line<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a '''class''' named '''Product''' in this example.<br /> <br /> <br /> I have declared '''attr_accessor '''for''' name and price.'''<br /> <br /> <br /> That is all that is required to use these types of '''methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight object creation logic.<br /> <br /> <br /> <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us put it to action. <br /> <br /> <br /> I have initialized a '''Product''' '''object'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''setter''' logic.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then I have set the '''name''' and '''price''' of the '''product object'''.<br /> <br /> <br /> This is possible because the '''attr_declaration,''' by default, creates '''methods''' for setting values.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''getter''' logic.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have then attempted to print the values using the '''getter''' '''methods''' for '''name''' and '''price'''.<br /> <br /> <br /> These '''getter methods''' were also generated by the declaration of '''attr_accessor'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us execute the code like before.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice that it prints the values that were set.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| By now you should be able to write your own '''accessor methods'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| '''Slide'''<br /> <br /> '''Accessor Methods'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| One thing to note is that '''accessor methods''' are, by default,''' instance methods.'''<br /> <br /> <br /> Thus they can be accessed by different '''instances''' of the '''class Product'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide<br /> <br /> Summary<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| In this tutorial we have learnt about:<br /> <br /> * '''instance methods'''<br /> * '''class methods '''and <br /> * '''accessor methods'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide<br /> <br /> Assignment<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| As an assignment:<br /> <br /> * Define a '''class''' named '''Temperature'''<br /> * Write an '''instance method '''using '''Ruby's''' '''accessor method''' syntax.<br /> * This '''method''' should calculate the '''Celsius '''for the given '''Fahrenheit.'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide<br /> <br /> About the Spoken Tutorial Project<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Watch the video available at the following link.<br /> <br /> It summarizes the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials<br /> <br /> Gives certificates to those who pass an online test<br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide<br /> <br /> Acknowledgments<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Previous Slide<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| This is Anjana Nair signing off. Thank you<br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/File:Object_Oriented_Programming_Part_1-11Aug2014_V1.1.pdf 2014-12-18T06:04:48Z

<p>Anjana: </p> <hr /> <div></div>

Anjana https://script.spoken-tutorial.org/index.php/Ruby/C3/Object-Oriented-Concept-in-Ruby/English 2014-03-12T04:19:31Z

<p>Anjana: Classes and Object Oriented Concept in Ruby</p> <hr /> <div>'''Title of script: Object Oriented concept in Ruby'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> <br /> '''Keywords: class'''<br /> <br /> <br /> <br /> {| style=&quot;border-spacing:0;&quot;<br /> | style=&quot;border-top:0.05pt solid #000000;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| &lt;center&gt;'''Visual Cue'''&lt;/center&gt;<br /> | style=&quot;border:0.05pt solid #000000;padding:0.097cm;&quot;| &lt;center&gt;'''Narration'''&lt;/center&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 1<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Welcome to this spoken tutorial on '''Object Oriented Concept '''in '''Ruby.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 2<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| In this tutorial we will learn to use-<br /> <br /> * '''classes'''<br /> * '''creating objects'''<br /> * '''accessordifferent ways of defining methods in ruby '''and other kinds of''' methods'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 3<br /> <br /> System Requirements<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here we are using<br /> <br /> * '''Ubuntu '''version 12.04<br /> * '''Ruby'''1.9.3<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 4<br /> <br /> Pre-requisites<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| To follow this tutorial, you must have '''Internet '''Connection.<br /> <br /> <br /> You must also have knowledge of '''Linux '''commands, '''Terminal '''and '''Text-editor.'''<br /> <br /> <br /> If not, for relevant tutorials, please visit our website.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Before we begin, recall that we had created “'''ttt'''” directory earlier.<br /> <br /> <br /> Let's go to that directory.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the '''terminal''' which has all the commands for creating the directories and the prompt should be in '''classes '''directory<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then to '''ruby-tutorial '''and '''classes''' directory.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 5<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Ruby''' is an object oriented language. <br /> <br /> Everything in '''Ruby''' is an object; from a value to a '''string''' or number. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 6 – What is a Class in Ruby?<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| A '''class''' is a collection of related '''data''' and '''functions'''.<br /> <br /> It can serve to keep information organized.<br /> <br /> An '''object''' is an '''instantiation''' of a '''class'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 7<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| A '''class''' definition begins with the keyword '''class.'''<br /> <br /> It is followed by the name of the '''class.'''<br /> <br /> It is delimited with an '''“end”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us look at an example of a '''class.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 8<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''class Product'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> The name of the '''class''' must begin with a capital letter.<br /> <br /> Names that contain more than one word should be separated by an '''“underscore (_)”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit''' where you have already opened the file '''“class_definition.rb” '''with the class defnition''' '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''class_definition.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of the implementing '''classes'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''“Order”'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a''' class '''named''' Order''' in this example.<br /> <br /> Now let us make the '''class '''useful by adding some '''variables'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| HIghlight '''“@myinstance”'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then I have defined an '''instance variable “myinstance”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the value<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have assigned a value to it.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''“@myclassvar”'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have also defined a '''class variable “myclassvar”'''<br /> <br /> And I have assigned a value to it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal''' type<br /> <br /> '''Order.instance_variables'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us switch add some code that will make use of this class. to the''' terminal '''and tType''' puts Order dot instance underscore variables. '''<br /> <br /> '''Before this line, “puts” some characters and slash n for a new line.'''<br /> <br /> '''This is done for readability. '''<br /> <br /> '''Let us copy and paste that and add it just below the line we added and save it.'''<br /> <br /> <br /> '''Now let us execute this code.'''<br /> <br /> '''Switch to the terminal and type ruby class_definition.rb and see the output.'''<br /> <br /> <br /> This is to see the''' instance variables '''of the class '''“Order”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Point to the output<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Inspect the output.<br /> <br /> You will see all the''' instance variable you defineds''' of''' class “Order”.'''<br /> <br /> From that list you can spot the one that you defined in the '''class.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Not sure if this is a repetition of the above 2 rows.Next let us type execute''' Order.class_variables .'''<br /> <br /> '''Let us copy and paste the demarcation just below the line and save it.'''and inspect the output.''' '''<br /> <br /> Now let us switch to the terminal and execute the file like before.<br /> <br /> You will notice the '''class variable '''you defined also show up.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You should now be able to write your own''' class.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next, let us look at what an '''object '''is.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 9 – What is an object?<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| An''' object''' is an '''instance '''of a '''class.'''<br /> <br /> Which means an''' object '''is created from a '''class.'''<br /> <br /> An''' object '''will have the properties and''' methods '''defined in the '''class.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 10 – How do you declare an object<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| We declare an '''object''' of a '''class '''using the '''new''' keyword.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 11<br /> <br /> <br /> <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here we are declaring an '''object '''of the''' Product class.'''<br /> <br /> Here an '''object '''gets created.<br /> <br /> '''product = Product.new'''<br /> <br /> This process is called''' initialization '''of an''' object.'''<br /> <br /> This '''object''' is of '''type : Product.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 12<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let is look at what an '''“initialize” method '''is.<br /> <br /> An''' initialize method''' is called at the time of '''object''' creation.<br /> <br /> <br /> In our previous examples we declared''' objects.'''<br /> <br /> <br /> On declaringcalling new on an '''object''' we have invoked the''' initialize method.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 13<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| An '''initialize method '''may take a list of parameters.<br /> <br /> <br /> Like other '''Ruby methods,''' it is preceded by the '''“def” '''keyword.<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to gedit where you have already opened the file “object_initialize.rb” with the '''object initialize '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it '''object_initialize.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of the '''object initialization''' code.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''class Order'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here I have defined a '''class '''called''' “Order”'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight''' initialize method'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then I have defined the '''initialize method '''with no '''argument.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the''' puts '''declaration<br /> <br /> <br /> <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a '''puts method''' to display the message''' “I have created an object”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Then highlight next line that declares the''' object.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next I have defined''' Order.new.'''<br /> <br /> This will invoke the '''initialize method.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type<br /> <br /> '''ruby object_initialize.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the '''terminal '''and type<br /> <br /> '''ruby object underscore initialize dot rb '''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Point to the output<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will see the message''' “I have created an object” '''printed out.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us go back to '''gedit''' and add an '''argument''' to the '''method.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the code with''' puts.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us modify the '''puts '''code.<br /> <br /> It should display the value of the '''argument''' passed.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Visual Cue is missing<br /> <br /> Highlight the line Order.new<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us call''' type '''<br /> <br /> '''Order.new(“I have initialized youcreated an object”).'''<br /> <br /> Here we have given an '''argument '''to the''' new method.'''<br /> <br /> This''' argument''' gets passed on to the''' initialize method.'''<br /> <br /> '''Next let us replace the string with “arg”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the '''terminal '''and type<br /> <br /> '''ruby object_initialize.rb''' and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will see''' '''the message '''“I have initialized youcreated an object”''' printed out.<br /> <br /> Now, you would have understood what '''object initialization '''means.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 14 – Defining methods in a class<br /> <br /> <br /> Each '''method '''in a '''class '''is defined within the''' “def” “end” '''block.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Recall that in '''Ruby, methods '''are the '''functions '''that a''' class''' performs.<br /> <br /> <br /> Each '''method '''in a '''class '''is defined within the''' “def” “end” '''block.<br /> <br /> <br /> A multiword''' method '''name is separated with an''' underscore.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 154 – Defining methods in a class<br /> <br /> '''contd...'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Some of the characters that can be appended to a '''method '''name are:<br /> <br /> * '''?'''<br /> * '''&lt;nowiki&gt;=&lt;/nowiki&gt;'''<br /> <br /> Each of the characters add some meaning to the '''method.'''<br /> <br /> Let us look at some examples.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to gedit.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it '''class_methods.rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of '''class methods''' code.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''class Animal'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here I have defined a''' class '''named''' “Animal”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Then highlight '''methods breathe '''and''' walk'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Then I have two '''methods “breathe” '''and''' “walk”.'''<br /> <br /> They are both defined with the '''“def” '''and''' “end” '''keywords.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight '''Animal.new'''<br /> <br /> Then highlight '''animal.breathe''' and then<br /> <br /> '''animal.walk'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have then initialized the '''object Animal.'''<br /> <br /> I have assigned it to a variable called''' “animal” with lowercase “a”.'''<br /> <br /> Then I have invoked the '''methods “breathe” '''and''' “walk” '''consequtively.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type<br /> <br /> '''ruby class_methods.rb'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us execute the program.<br /> <br /> <br /> Switch to the '''terminal '''and type<br /> <br /> '''ruby class underscore methods dot rb '''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the output.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice the lines:<br /> <br /> '''“ I breathe”'''<br /> <br /> '''“ I walk”'''<br /> <br /> printed out.<br /> <br /> This is because you have invoked the''' '''two''' methods “breathe” '''and '''“walk”.'''<br /> <br /> These '''methods '''are invoked on lines 15 and 16 respectively.<br /> <br /> <br /> A '''“puts”''' statement defined within these '''methods''' gives the results you see.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us look at how to create '''methods '''with a trailing '''question mark.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to''' gedit.'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it '''class underscore methods underscore with underscore trailing underscore characters dot rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| In '''gedit'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have a working example of '''class methods '''with '''question mark''' code.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight''' “breathe?” '''line<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Here I have taken the same '''class''' as before as an example.<br /> <br /> Here the '''breathe method''' has a trailing '''“question mark (?)”.'''<br /> <br /> Such '''methods '''are generally used to return''' boolean values.'''<br /> <br /> <br /> This is based on the '''method '''naming''' '''convention of '''Ruby.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight''' animal.breathe?'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| The '''method''' gets invoked by declaring''' animal.breathe?'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type<br /> <br /> '''ruby class_methods_with_trailing_characters.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the '''terminal '''and type<br /> <br /> '''ruby class underscore methods underscore with underscore trailing underscore characters dot rb'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice the output as :<br /> <br /> '''“true”'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight''' “walk=(value)” method'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us define another '''method '''called''' “walk”.'''<br /> <br /> Let us place an '''equal-to '''sign '''(“=(value)”) '''beside it.<br /> <br /> The let us execute this '''method.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type<br /> <br /> '''ruby class_methods_with_trailing_characters.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the '''terminal '''and type<br /> <br /> '''ruby class underscore methods underscore with underscore trailing underscore characters dot rb'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the error<br /> <br /> <br /> <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| It will give an '''“undefined method”''' error.<br /> <br /> <br /> This is because the '''equal to sign''' has another meaning.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type the code<br /> <br /> '''animal.walk = “ hops”'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| It is used to assign a value to the '''method.'''<br /> <br /> So, let us invoke the '''method '''a little differently this time.<br /> <br /> <br /> '''animal.walk = “ hops”'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let give it another try.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''type<br /> <br /> '''ruby class_methods_with_trailing_characters.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Switch to the '''terminal '''and type<br /> <br /> '''ruby class underscore methods underscore with underscore trailing underscore characters dot rbrub the command like before.'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| On the '''terminal '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice that the word '''“hops”''' get printed.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| This demonstrates that the''' equal to sign''' next to a '''method''' means '''assignment.'''<br /> <br /> Now you should be able to write your own''' methods.'''<br /> <br /> <br /> This script is too long. I think you should cut it into 2 topics, with the first topic ending here.'''&lt;nowiki&gt;&lt;PAUSE&gt;&lt;/nowiki&gt;'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 15 – Defining accessor methods in a class<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| There are three ways of defining '''accessor methods''' in a '''class'''<br /> <br /> * '''attr_reader'''<br /> * '''attr_writer'''<br /> <br /> '''attr_accessor '''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 15 contd...<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| * An''' attr_reader method '''is used to define an '''accessor method '''for an''' attribute''' of a '''class.'''<br /> * An''' attr_write method '''is used to define a '''setter method '''for an''' attribute '''of a '''class. '''This '''method '''enables you to set a value for the''' '''specified''' attribute.'''<br /> * An''' attr_accessor method''' can define both a''' getter '''and a '''setter method''' for the specified '''attribute. '''By default, the name of the '''methods''' that are generated will be the same name as the''' attribute.'''<br /> <br /> * Let us look at an example.<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to '''gedit'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Create a new file in gedit as shown in the basic level Ruby tutorials.'''<br /> <br /> <br /> And name it '''class underscore attribute underscore accessors dot rb'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''class definition.'''<br /> <br /> Highlight the next line that has '''attr_reader'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| I have defined a '''class Product''' like before.<br /> <br /> Then I have declared''' attr_reader :name.'''<br /> <br /> This will generate a '''method '''that will return the value of '''“name”'''.<br /> <br /> Since '''“name” '''is not defined,''' '''this declaration is meaningless.<br /> <br /> It will add value only if you have a '''method '''that assigns a value to '''“name”.'''<br /> <br /> So, we have defined an '''attr_writer :name.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the''' object initialization '''line.<br /> <br /> Then highlight the '''puts '''line.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us initialize an''' object''' of''' class Product.'''<br /> <br /> Then let us call the''' method “name”''' on it.<br /> <br /> Then we will use '''puts '''to print the value returned.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| '''On the terminal type'''<br /> <br /> '''ruby class_attribute_accessors.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Switch to the terminal and type'''<br /> <br /> '''ruby class underscore attribute underscore accessors dot rb '''<br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Point to the '''terminal'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| There will be no output.<br /> <br /> This is because the''' “name” attribute''' does not have any value assigned to it.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Back on '''gedit'''<br /> <br /> Type the code<br /> <br /> '''product.name = “ipad”'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| So, now let us assign a value to''' “name”.'''<br /> <br /> Type '''product.name = “ipad”.'''<br /> <br /> Now switch to the''' terminal '''again and execute the code like before.<br /> <br /> <br /> This time you will notice the value getting returned.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the '''puts “The name of the product is” '''part of the code.<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Let us modify the '''“puts” '''so that the sentence is more meaningful.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us execute the code and inspect the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Point to the output<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| The output will say '''“The name of the product is ipad”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Next let us define an '''attr_accessor''' for''' “price”.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Visual Cue missing<br /> <br /> Is this a slide or will you point to some code<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now let us use this''' accessor '''by defining<br /> <br /> '''product.price.'''<br /> <br /> Since this''' method''' acts as a '''value setter '''and a '''getter''', let us:<br /> <br /> * assign a value to the '''price attribute'''<br /> <br /> and get the value it contains<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type the code.<br /> <br /> '''puts “The price of the product is: “+ product.price.to_s'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Lets declare''' product.price = 50000.'''<br /> <br /> Then let us use '''“puts”''' to print the value of''' price.'''<br /> <br /> So we type<br /> <br /> '''puts “The price of the product is: “+ product.price.to_s'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| '''On the terminal type'''<br /> <br /> '''ruby class_attribute_accessors.rb '''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| '''Switch to the terminal and type'''<br /> <br /> '''ruby class underscore attribute underscore accessors dot rb '''<br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| You will notice the string declared with''' “puts” '''gets displayed.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Now you should be able to write your own '''attribute accessors, readers and writers.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| '''Slide 16 -- Assignment'''<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| As an assignment:<br /> <br /> * Define a '''class '''called''' Product'''<br /> * Define an''' attr_accessor '''for name of the product.<br /> * During '''object intialization '''use the '''accessor methods '''to''' set '''and''' get '''value for '''“name”'''.<br /> * In the same '''object initialization method '''assign the value of '''“name”''' to an''' instance variable.'''<br /> * Define a separate''' method''' to access this''' instance variable.'''<br /> <br /> The output should be in the format: '''“The product was initialised with this name: #{product_object.prod_name}”'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 16<br /> <br /> Summary<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| In this tutorial we have learnt-<br /> <br /> * '''How to declare classes'''<br /> * '''How to create objects of a class'''<br /> * '''Different ways of defining methods in ruby'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 17<br /> <br /> Assingment<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| As an assignment:<br /> <br /> * Define a class Product<br /> * Define methods that you can use get values of “myvar” and set values for “myvar”.<br /> * To set values define the method using “=” sign.<br /> * Instantiate the object of the class and set and get values using the above 2 methods.<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 182<br /> <br /> About the Spoken Tutorial Project<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Watch the video available at the following link.<br /> <br /> It summarizes the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 193<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials<br /> <br /> Gives certificates to those who pass an online test<br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 2014<br /> <br /> Acknowledgements<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: <br /> <br /> spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:none;padding:0.097cm;&quot;| Previous slide<br /> | style=&quot;border-top:none;border-bottom:0.05pt solid #000000;border-left:0.05pt solid #000000;border-right:0.05pt solid #000000;padding:0.097cm;&quot;| This is Anjana Nair signing off. Thank you<br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/Ruby/C2/Control-Statements/English 2013-09-05T06:43:07Z

<p>Anjana: Created page with ''''Title of script''': '''Control Statements''' '''Author: Anjana Nair''' '''Keywords: if, elsif, else, case, statements loop, Ruby, video tutorial''' {| style=&quot;border-spac…'</p> <hr /> <div>'''Title of script''': '''Control Statements'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> <br /> '''Keywords: if, elsif, else, case, statements loop, Ruby, video tutorial'''<br /> <br /> <br /> <br /> {| style=&quot;border-spacing:0;&quot;<br /> | style=&quot;background-color:#ffffff;border-top:1pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;center&gt;'''Visual Cue'''&lt;/center&gt;<br /> | style=&quot;background-color:#ffffff;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;center&gt;'''Narration'''&lt;/center&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 1<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Welcome to the spoken tutorial on Control Statements''' '''in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 2<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| In this tutorial we will learn to use-<br /> <br /> * '''if''' '''statement'''<br /> * '''elsif'''<br /> * '''else'''<br /> * '''case statements'''&lt;br/&gt; <br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 3<br /> <br /> System Requirements<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Here we are using<br /> <br /> * '''Ubuntu '''version 12.04<br /> * '''Ruby'''1.9.3<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 4<br /> <br /> Pre-requisites<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| To follow this tutorial, you must have '''Internet '''Connection.<br /> <br /> <br /> You must also have knowledge of '''Linux '''commands, '''Terminal '''and '''Text-editor.'''<br /> <br /> <br /> &lt;nowiki&gt;If not, for relevant tutorials, please visit our website. &lt;&lt;PAUSE&gt;&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Before we begin, recall that we had created “'''ttt'''” directory earlier.<br /> <br /> <br /> Let's go to that directory.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to the terminal window which has all the commands for creating the directories and the prompt should be in '''control-statements '''directory<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then to '''ruby-tutorial '''and '''control-statements''' directory.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now that we are in that folder, let’s move ahead.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 5<br /> <br /> The “if-statement”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax of the '''if statement''' in '''Ruby''' is as follows:<br /> <br /> <br /> '''if “condition”'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “if-statement.rb” with the '''if statement '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''if-statement.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| control-statements<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''if statement'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “if” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''if statement''' in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “my_num”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| First, I declare a local variable '''my_num''' and assign the value '''2345''' to it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the '''if '''condition.<br /> <br /> Then highlight the string to be displayed as output.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I declare an '''if''' statement.<br /> <br /> The '''puts''' method declared within the '''if''' statement will display the output.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''if''' '''statement''' will check if the value of '''my_num''' is greater than '''0'''. <br /> <br /> If it is, it will print out the specified '''string.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now, let us switch to the '''terminal '''and type<br /> <br /> '''ruby if-statement.rb'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will display “'''The value of my_num is greater than 0'''”.<br /> <br /> This output proves that the '''if '''condition returned '''true'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own '''if''' '''statement''' in '''Ruby'''.<br /> <br /> <br /> Let's look at the '''if-else statement '''next.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 6<br /> <br /> The “if-else statement”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax for using '''else''' is:<br /> <br /> <br /> '''if “condition” '''<br /> <br /> '''ruby code'''<br /> <br /> '''else'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “if-else-statement.rb” with the '''if statement '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''if-else-statement.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''if-else statement'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “if” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''if-else statement''' in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “my_num”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| First I declare a local variable '''my_num''' and assign the value of '''-1 '''to it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the '''if '''condition.<br /> <br /> Then highlight the string to be displayed as output.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I declare an '''if''' statement.<br /> <br /> The '''if''' statement will check if the value of '''my_num''' is greater than '''0'''. <br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| If it is, it will print out the specified '''string.''' <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the '''else '''condition.<br /> <br /> Then highlight the string to be displayed as output.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| If not, it will go to the '''else statement'''. <br /> <br /> <br /> And it will print out the '''string''' that is specified there.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now, let us switch to the '''terminal '''and type<br /> <br /> '''ruby if-else-statement.rb'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will display “'''The value of my_num is lesser than 0'''”.<br /> <br /> <br /> This shows that the '''else statement''' was executed.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own '''if-else''' '''statement''' in '''Ruby'''.<br /> <br /> <br /> Let's look at the '''if-elsif statement '''next.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 7<br /> <br /> The “if-elsif” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax for using '''elsif''' is:<br /> <br /> <br /> '''if “condition” '''<br /> <br /> '''ruby code'''<br /> <br /> '''elsif “condition”'''<br /> <br /> '''ruby code'''<br /> <br /> '''else'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “if-elsif-statement.rb” with the '''if statement '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''if-elsif-statement.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''if-elsif- statement'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “if” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''if-elsif statement''' in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “my_num”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Here also, I have declare a local variable '''my_num '''and assign the value '''-1 '''to it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the '''if '''condition.<br /> <br /> Then highlight the string to be displayed as output.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I declare an '''if''' '''statement'''.<br /> <br /> The '''if''' '''statement''' will check if the value of '''my_num '''is greater than '''0'''. <br /> <br /> If it is, it will print out the specified string. <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| If this is not '''true''', it will go into the '''elsif''' section. <br /> <br /> It will now check if the value of '''my_num''' is equal to '''-1'''. <br /> <br /> If it is true, it will print out the string that is specified there. <br /> <br /> If the value of my_num is neither greater than 0 nor equal to -1 it will go into the else section.<br /> <br /> But since the value of my_num = -1 it will not proceed to the else block.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| And it will exit the conditional '''statement'''.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now, let us switch to the '''terminal '''and type<br /> <br /> '''ruby if-elsif-statement.rb'''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will display “The value of '''my_num''' is '''-1''' and is lesser than '''0'''”.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's go back to our file and change the value of '''my_num '''to 5.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's save the code and execute it on the terminal.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| So, now it fulfills the if condition and the specified string is printed.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's go back to our file and change the value of '''my_num '''to '''-5'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's save the code and execute it on the terminal.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| In this case it fulfills the '''else''' condition and the puts statement within the else block gets executed.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own '''if- elsif''' '''statement''' in '''Ruby'''.<br /> <br /> <br /> Let's look at the '''case statement '''next.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 8<br /> <br /> The “case statement”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''case''' '''statement''' is a '''control flow statement''' based on a particular selection.<br /> <br /> Let us look at the syntax of the '''case statement '''in order to understand this statement.<br /> <br /> The syntax for using '''case''' is:<br /> <br /> <br /> '''case variable'''<br /> <br /> '''when “value 1” '''<br /> <br /> '''ruby code'''<br /> <br /> '''when “value 2”'''<br /> <br /> '''ruby code'''<br /> <br /> '''when “value 3”'''<br /> <br /> '''ruby code'''<br /> <br /> '''else'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “case-statement.rb” with the case-statement''' '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''case-statement.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''case statement'''.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “case” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''case statement''' in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the “print” statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Here I have a '''print''' '''statement''', which will print a question on the terminal.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “gets”.''' '''<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I call a '''gets,''' which will accept a single line of data from the standard input.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then highlight “gets.chomp”.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I strip the input data of any '''new line characters''' using '''chomp'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then highlight “domain”.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I assign the result to a variable named '''domain.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “when”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I declare a case statment.<br /> <br /> Within that I declare a '''when''' '''statement''' .<br /> <br /> This checks whether the specified string matches value of '''domain'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight when &quot;UP&quot;<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| First it checks whether the value of '''domain''' is '''“UP”'''.<br /> <br /> If it is so, it will print out '''“Uttar Pradesh” '''and exit the '''case statement.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight when &quot;MP&quot;<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| If '''domain '''is not “'''UP”''', it checks whether the value of '''domain''' is '''“MP”.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight puts &quot;Madhya Pradesh&quot;<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| If it is so, it will print out '''“Madhya Pradesh”''' and so on...<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the when statements below the statements mentioned above.<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| It will continue checking the value of '''domain''' if no match was found so far.<br /> <br /> At this point it will encounter the '''else''' '''statement '''<br /> <br /> as none of the above conditions were true.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight else statement<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| It will subsequently execute the '''ruby code '''that follows the '''else''' declaration.<br /> <br /> <br /> It will print “'''Unknown'''” as per our example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to terminal<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now, save the file, switch to the '''terminal '''and type<br /> <br /> '''ruby case-statement.rb. '''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| “'''Enter the state you live in:'''” will be displayed on the '''terminal.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Type “UP”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Type in “'''UP'''” and see the output.<br /> <br /> <br /> The output will display '''“Uttar Pradesh”.'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Next execute the '''Ruby''' file again, like before.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Type “KL”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This time at the prompt type in '''“KL” '''and see the output.<br /> <br /> <br /> It will print '''“Kerala”'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Next execute the file one more time.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Type “TN”<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This time at the prompt type in '''“TN”''' and see the output.<br /> <br /> <br /> It will print '''“Unknown”'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This is because none of the '''cases '''were satisfied. So, the default '''else statement '''is executed.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own''' case-statements '''in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 9<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;nowiki&gt;&lt;&lt;Pause&gt;&gt;&lt;/nowiki&gt;<br /> <br /> This brings us to the end of this Spoken Tutorial.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 10<br /> <br /> Summary<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's summarize.<br /> <br /> In this tutorial we have learnt to use<br /> <br /> * '''if''' '''statement'''<br /> * '''else''' construct<br /> * '''if-elsif '''and<br /> * '''case statements'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 11<br /> <br /> Assignment<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| As an assignment :<br /> <br /> Write a '''Ruby''' program :<br /> <br /> * that prompts a user to enter a number<br /> <br /> * then use the appropriate control-statement<br /> * to check if the number is a multiple of 2<br /> * if it is, then print “The number entered is a multiple of 2”<br /> * if not, it should check if it is a multiple of 3<br /> * if it is, then print “The number entered is a multiple of 3”<br /> * if not, it should check if it a multiple of 4<br /> * if it is, then print “The number entered is a multiple of 4”<br /> * if not, it should print “The number is not a multple of 2, 3 or 4”<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| lide 12<br /> <br /> About the Spoken Tutorial Project<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Watch the video available at the following link.<br /> <br /> It summarizes the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it. <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 13<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials<br /> <br /> Gives certificates to those who pass an online test<br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 14<br /> <br /> Acknowledgements<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: <br /> <br /> spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This is Anjana Nair signing off. Thanks for watching (or joining or whatever else ....)<br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/Ruby/C3/for-and-each-Looping-Statements/English 2013-06-27T03:35:58Z

<p>Anjana: </p> <hr /> <div>'''Title of script''': '''Looping Statements'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> '''Keywords: for, each, loop, Ruby, video tutorial'''<br /> <br /> {| border=1<br /> || '''Visual Cue'''<br /> || '''Narration'''<br /> <br /> |-<br /> | Slide 1<br /> | Welcome to the tutorial on '''for '''and '''each Loops''' in '''Ruby'''.<br /> <br /> |-<br /> | Slide 2<br /> | In this tutorial we will learn<br /> <br /> * Meaning of the term “loop”<br /> * The different kinds of loops in '''Ruby'''<br /> * Usage of “'''for'''” loop and<br /> * Usage of “'''each'''” looping construct<br /> <br /> |-<br /> | Slide 3<br /> <br /> System Requirements<br /> | Here we are using<br /> <br /> * '''Ubuntu''' version 12.04<br /> * '''Ruby''' 1.9.3<br /> <br /> |-<br /> | Slide 4<br /> <br /> Pre-requisites<br /> | To follow this tutorial, you must have '''Internet''' Connection.<br /> <br /> You must also have knowledge of '''Linux''' commands, '''Terminal''' and '''Text-editor.'''<br /> <br /> If not, for relevant tutorials, please visit our website.<br /> <br /> |-<br /> | <br /> | Now let me explain what is referred to as a “'''loop'''” in '''Ruby'''.<br /> <br /> |-<br /> | Slide 5<br /> <br /> What is a loop?<br /> | A '''loop '''is a command or set of commands that are executed a fixed number of times.<br /> <br /> |-<br /> | Slide 6<br /> <br /> Looping statements<br /> | '''Ruby''' has the following main looping statements.<br /> <br /> * '''for '''<br /> * '''each'''<br /> * '''while'''<br /> * '''until '''<br /> <br /> |-<br /> | <br /> | In this tutorial we will learn how to use the '''for''' and '''each''' looping constructs.<br /> <br /> <br /> <br /> |-<br /> | Type mkdir ttt and press Enter <br /> | Before we begin, please create the following folders in your home directory,ttt, ruby-tutorial, looping-statements. please create the sub- folder as mentioned here. <br /> <br /> <br /> |-<br /> | <br /> | Now we have created the requisite folders. <br /> <br /> <br /> Let's move ahead.<br /> <br /> |-<br /> | Slide 7<br /> <br /> “for” loop<br /> | The syntax of the “'''for'''” loop in '''Ruby''' is as follows:<br /> <br /> '''for “variable” in “a collection of objects”'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> Let us try to understand it with an example. <br /> <br /> |-<br /> | Switch to gedit where you have already opened the file “for-loop.rb” with the '''for loop '''code typed inside.<br /> | Create a new file in '''gedit''' as shown in the basic level '''Ruby '''tutorials.<br /> <br /> And name it “'''for-loop.rb'''”<br /> <br /> |-<br /> | <br /> | I already have a working example of the “'''for”''' loop. <br /> <br /> You can type the code as we go through this example.<br /> <br /> <br /> |-<br /> | Highlight “for”<br /> | I have declared a “'''for”''' loop in this example.<br /> <br /> |-<br /> | Highlight (1..20)<br /> | We have a set of numbers 1 to 20.<br /> <br /> |-<br /> | Highlight “for i in (1..20)”<br /> | We declare a variable called “'''i'''” within the “'''for”''' loop.<br /> <br /> |-<br /> | Continue the highlight<br /> | The variable '''“i” '''gets initialized to the first element in the set of numbers 1 to 20.<br /> <br /> |-<br /> | Continue the highlight<br /> | The “'''for'''” loop declaration causes the code to iterate over each element in the set 1 to 20. <br /> <br /> |-<br /> | Highlight “puts”<br /> | The “'''puts'''” method declared within the “'''for'''” loop is responsible for generating the output.<br /> <br /> |-<br /> | Switch to the terminal and type <br /> <br /> ruby for-loop.rb<br /> <br /> <br /> Point to the output<br /> | Now open the '''terminal''' and type <br /> <br /> “'''ruby for-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | Analyzing the output<br /> | The output will be an '''array''' of numbers 1 to 20.<br /> <br /> |-<br /> | <br /> | In this example, we declared a “'''for'''” loop for an inclusive range.<br /> <br /> It included all numbers from 1 to 20.<br /> <br /> |-<br /> | <br /> | Next we shall look at implementing the “'''for'''” loop for a non-inclusive range.<br /> <br /> <br /> |-<br /> | <br /> | Continue to type the next part of the code.<br /> <br /> |-<br /> | Highlight “for i in (1...20)”<br /> | Non-inclusive means it will not include the last element in the collection of objects.<br /> <br /> |-<br /> | Continue the highlight<br /> | Here a “'''for'''” loop is implemented for a non-inclusive range of numbers 1 to 20.<br /> <br /> |-<br /> | Continue the highlight<br /> | You will notice shortly that the number 20 will not be printed in the output.<br /> <br /> |-<br /> | Highlight the 3 dots only<br /> | The last digit does not get included when you have 3 dots between numbers.<br /> <br /> |-<br /> | Switch to the terminal and type <br /> <br /> ruby for-loop.rb<br /> <br /> <br /> Point to the output<br /> | '''Now open the terminal and type “'''ruby for-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | Analyzing the output<br /> | The output will still be an array of numbers but will not include the number 20.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | <br /> | Now, you should be capable enough to write your own “'''for'''” loop.<br /> <br /> |-<br /> | Slide 8<br /> <br /> “each” loop<br /> | The syntax of the “'''each'''” loop in '''Ruby '''is as follows:<br /> <br /> '''“a collection of objects”.each do |item|'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us try to understand it with an example. <br /> <br /> |-<br /> | Switch to gedit where you have already opened the file “each-loop.rb” with the '''each loop '''code typed inside.<br /> | Create a new file in '''gedit''' as shown in the basic level '''Ruby''' tutorials.<br /> <br /> <br /> And name it “'''each-loop.rb'''”<br /> <br /> |-<br /> | <br /> | I already have a working example of the “'''each”''' loop. <br /> <br /> <br /> You can type the code as we go through this example.<br /> <br /> <br /> <br /> <br /> |-<br /> | Highlight “for”<br /> | I have declared an “'''each'''” loop in this example.<br /> <br /> We have a set of numbers 1 to 20.<br /> <br /> |-<br /> | Highlight “for i in (1..20)”<br /> | We declare a variable called “'''i'''” within the “'''each'''” loop.<br /> <br /> |-<br /> | Continue the highlight<br /> | The “'''i'''” variable gets initialized to the first element in the set of numbers 1 to 20.<br /> <br /> |-<br /> | Continue the highlight<br /> | The '''“each”''' loop declaration causes the code to iterate over each element in the set 1 to 20. <br /> <br /> |-<br /> | Highlight “puts”<br /> | The “'''puts'''” method declared within the “'''each'''” loop is responsible for generating the output.<br /> <br /> |-<br /> | Switch to the terminal and type “'''ruby each-loop.rb'''” <br /> | Now open the '''terminal''' and type “'''ruby each-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | Analyzing the output<br /> | The output will be an array of numbers 1 to 20.<br /> <br /> |-<br /> | <br /> | In the above example we declared an “'''each'''” loop for an inclusive range.<br /> <br /> <br /> It included all numbers from 1 to 20.<br /> <br /> |-<br /> | <br /> | Next we shall look at implementing the “'''each'''” loop for a non-inclusive range.<br /> <br /> |-<br /> | Switch back to gedit<br /> | Let's get back to the same file we were looking at.<br /> <br /> |-<br /> | <br /> | Continue to type the next part of the code.<br /> <br /> |-<br /> | Highlight “for i in (1...20)”<br /> | Non-inclusive means it will not include the last element in the collection of objects.<br /> <br /> |-<br /> | Continue the highlight<br /> | Here a “'''each'''” loop is implemented for a non-inclusive range of numbers 1 to 20.<br /> <br /> |-<br /> | Continue the highlight<br /> | You will notice shortly that the number 20 will not be printed in the output.<br /> <br /> |-<br /> | Highlight the 3 dots only<br /> | The last digit does not get included when you have 3 dots between numbers.<br /> <br /> |-<br /> | Switch to the terminal and type <br /> <br /> ruby each-loop.rb<br /> <br /> <br /> Point to the output<br /> | '''Now open the terminal and type “'''ruby each-loop.rb'''”<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | <br /> | Now you should be capable enough to write your own “'''each'''” loop.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | Slide 9<br /> | How would we determine which looping construct to choose?<br /> <br /> Let us try to recall the “'''for'''” loop construct.<br /> <br /> |-<br /> | Open “for-loop.rb”<br /> | In the first example, we iterated over a set of numbers from 1 to 20 using “'''for'''”.<br /> <br /> <br /> Execute “ruby for-loop.rb” in you have to anyways and see the output.<br /> <br /> <br /> Now look at the code in '''gedit.'''<br /> <br /> |-<br /> | Highlight “for number in (1..20)”<br /> | When you invoke the “'''for'''” loop, Ruby is actually calling the “'''each'''” method behind the scenes.<br /> <br /> <br /> And calling “'''each'''” or '''“for”''' will generate the same output.<br /> <br /> |-<br /> | <br /> | Since the call to “'''for'''” in turn calls “each”, it is preferable to use the “'''each'''” loop instead.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | Slide 10<br /> | &lt;nowiki&gt;&lt;&lt;Pause&gt;&gt;&lt;/nowiki&gt;<br /> <br /> This brings us to the end of this Spoken Tutorial.<br /> <br /> Let's summarize.<br /> <br /> |-<br /> | Slide 11<br /> <br /> Summary<br /> | In this tutorial we have learnt<br /> <br /> * Usage of “'''for'''” loop<br /> * Usage of “'''each'''” construct<br /> * Reasoning behind using “'''each'''” instead of “'''for'''” <br /> * Examples of using the above looping constructs<br /> <br /> |-<br /> | Slide 12<br /> <br /> Assignment<br /> | As an assignment <br /> <br /> Write a ruby program using <br /> <br /> * the appropriate loop construct<br /> * to create an output of even numbers<br /> * from a set of numbers, say 1 to 20<br /> <br /> <br /> <br /> |-<br /> | Slide 13<br /> <br /> About the Spoken Tutorial Project<br /> | Watch the video available at the following link.<br /> <br /> It summarises the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it. <br /> <br /> |-<br /> | Slide 14<br /> | The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials <br /> <br /> Gives certificates to those who pass an online test <br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | Slide 15<br /> <br /> Acknowledgements<br /> | Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: <br /> <br /> spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Previous slide<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This [http://www.ruby-software.com/ i]s Anjana Nair signing off. Thank you<br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/Ruby/C3/while-and-until-Looping-Statements/English 2013-06-27T03:32:54Z

<p>Anjana: Created page with ''''Title of script''': '''Looping Statements''' '''Author: Anjana Nair''' '''Keywords: while, until, redo, break, loop, Ruby, video tutorial''' {| style=&quot;border-spacing:0;&quot;…'</p> <hr /> <div>'''Title of script''': '''Looping Statements'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> <br /> '''Keywords: while, until, redo, break, loop, Ruby, video tutorial'''<br /> <br /> <br /> <br /> {| style=&quot;border-spacing:0;&quot;<br /> | style=&quot;background-color:#ffffff;border-top:1pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;center&gt;'''Visual Cue'''&lt;/center&gt;<br /> | style=&quot;background-color:#ffffff;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;center&gt;'''Narration'''&lt;/center&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 1<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Welcome to the tutorial on '''while '''and '''until loops '''in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 2<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| In this tutorial we will learn to use-<br /> <br /> * '''while''' loop<br /> * '''until '''loop<br /> * '''redo'''<br /> * '''break'''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 3<br /> <br /> System Requirements<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Here we are using<br /> <br /> * '''Ubuntu '''version 12.04<br /> * '''Ruby'''1.9.3<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 4<br /> <br /> Pre-requisites<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| To follow this tutorial, you must have '''Internet '''Connection.<br /> <br /> <br /> You must also have knowledge of '''Linux '''commands, '''Terminal '''and '''Text-editor.'''<br /> <br /> <br /> If not, for relevant tutorials, please visit our website.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Before we begin, recall that we had created “ttt” directory earlier.<br /> <br /> <br /> Let's go to that directory.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to the terminal window which has all the commands for creating the directories and the prompt should be in '''looping-statements '''directory<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then to ruby-tutorial and looping-statements directory.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now that we are in that folder, let’s move ahead.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 5<br /> <br /> “while” loop<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax of the '''while''' loop in '''Ruby '''is as follows:<br /> <br /> <br /> '''while “boolean expression”'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “while-loop.rb” with the '''while loop '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> Name it '''while-loop.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''while '''loop.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “while”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared a '''while '''loop in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “i = 0”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| First, I declared a local variable '''i '''and initialized it with value '''0'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Continue the highlight “while i &gt;-10”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then I declare a '''while''' loop.<br /> <br /> This loop will execute as long as the variable '''i '''is greater than '''-10'''. <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “puts”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''puts''' method declared within the '''while''' loop will display the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “i -= 1”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| After the output is displayed, we decrement the value of '''i''' by 1.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| '''i''' will adopt this decremented value before the next iteration.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The variable '''i '''gets decremented in every iteration.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This goes on till i''' '''reaches the value '''-10''', <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| At this point the '''while condition '''fails.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| It subsequently breaks out of the loop and stops printing the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now, let us switch to the '''terminal '''and type<br /> <br /> '''ruby while-loop.rb''' <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the output:<br /> <br /> <br /> The number: 0 gets printed out<br /> <br /> The number: -1 gets printed out<br /> <br /> The number: -2 gets printed out<br /> <br /> The number: -3 gets printed out<br /> <br /> The number: -4 gets printed out<br /> <br /> The number: -5 gets printed out<br /> <br /> The number: -6 gets printed out<br /> <br /> The number: -7 gets printed out<br /> <br /> The number: -8 gets printed out<br /> <br /> The number: -9 gets printed out<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will consist of a list of numbers '''0''' through '''-9'''.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own '''while''' loop in '''Ruby'''.<br /> <br /> <br /> Let's look at the '''until''' loop next.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 6<br /> <br /> “until” loop<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax for the '''until''' loop in '''Ruby '''is -<br /> <br /> <br /> '''until “boolean expression”'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “until-loop.rb” with the '''loop '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it '''until-loop.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''until '''loop.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “until”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''until '''loop in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “i = 0”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| We had declared a local variable '''i '''and initialized it to '''0'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;nowiki&gt;Continue the highlight “until i &lt; -10” &lt;/nowiki&gt;<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then we declare an '''until''' loop.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This loop will execute as long as the variable '''i '''is greater than '''-10'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “puts”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''puts''' method will display the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “i -= 1”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| After the output is displayed, value of '''i''' is decremented by 1.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| '''i''' will adopt this decremented value before the next iteration.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The variable '''i '''gets decremented during every iteration.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This goes on till '''i '''reaches the value '''-11'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| At this point the '''until condition '''fails.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Subsequently, it breaks out of the loop and stops printing the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now switch to the '''terminal '''and type<br /> <br /> '''ruby until-loop.rb '''and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the output:<br /> <br /> <br /> The number: 0 gets printed out<br /> <br /> The number: -1 gets printed out<br /> <br /> The number: -2 gets printed out<br /> <br /> The number: -3 gets printed out<br /> <br /> The number: -4 gets printed out<br /> <br /> The number: -5 gets printed out<br /> <br /> The number: -6 gets printed out<br /> <br /> The number: -7 gets printed out<br /> <br /> The number: -8 gets printed out<br /> <br /> The number: -9 gets printed out<br /> <br /> The number: -10 gets printed out<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will consist of a list of numbers '''0''' through '''-10'''.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| You should now be able to write your own '''until''' loop in '''Ruby'''.<br /> <br /> Let's now move on to the '''redo''' construct.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 7<br /> <br /> “'''redo'''”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax for '''redo''' in '''Ruby '''is as follows:<br /> <br /> <br /> '''(a collection of objects).each do |item|'''<br /> <br /> '''a conditional statement on an item'''<br /> <br /> '''ruby code'''<br /> <br /> ''' redo'''<br /> <br /> '''end'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “redo-loop.rb” with the '''loop '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials, and name it '''redo-loop.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''redo '''loop.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through it.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “'''each'''”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''each '''loop in this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “(10..20).each do |i|”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| We have declared an '''each''' loop to iterate through numbers 10 to 20.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Continue the highlight “if i == 20”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Then, we define an '''if '''conditional statement.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Continue the highlight<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This loop will execute for every number between '''10 '''to '''20'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Continue the highlight<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| It will enter the inner '''if '''conditional block only if the value of '''i''' is equal to '''20'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “puts”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''puts''' method declared within the '''each''' loop displays the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Continue the highlight “if i == 20”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Once the program enters the '''if '''conditional block, it will first print the output.<br /> <br /> Then it will execute '''redo'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| '''redo''' will execute the iteration of the most internal loop.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| It will do so without checking the loop condition.<br /> <br /> Our condition being '''if i == 20'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The result will be an infinite loop, since the value of '''i''' will not change from '''20'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's switch to the '''terminal '''and type<br /> <br /> '''ruby redo-loop.rb''' <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the output:<br /> <br /> <br /> &gt;ruby redo-loop.rb<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> The value has reached it's limit 20<br /> <br /> ..................................................<br /> <br /> <br /> <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will consist of an infinite loop that never ends.<br /> <br /> <br /> Press Ctrl + c to terminate the infinite loop<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Next, let us look at the '''break''' statement.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 8<br /> <br /> “'''break'''” statement<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The syntax for the '''break''' statement in '''Ruby '''is -<br /> <br /> '''a looping statement'''<br /> <br /> '''a conditional statement'''<br /> <br /> '''break'''<br /> <br /> '''end conditional'''<br /> <br /> '''end loop'''<br /> <br /> <br /> Let us look at an example.<br /> <br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Switch to gedit where you have already opened the file “break-loop.rb” with the '''loop '''code typed inside.<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Create a new file in '''gedit '''as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it '''break-loop.rb'''<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have a working example of the '''break '''statement.<br /> <br /> <br /> You can pause the tutorial, and type the code as we go through this example.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “'''each'''”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| I have declared an '''each '''loop in this example.<br /> <br /> <br /> It is similar to the one we used earlier.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight “puts”<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The '''puts''' method here will display the output for numbers '''11''' to '''19'''.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| hHighlight “if” and then &quot;break&quot;<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Once the value becomes '''20,''' the program enters the conditional '''if''' block.<br /> <br /> <br /> At this point, it will encounter the '''break''' statement and break out of the loop.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now open the '''terminal '''and type<br /> <br /> '''ruby break-loop.rb '''<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Highlight the output:<br /> <br /> <br /> &gt;ruby break-loop.rb<br /> <br /> The value has reached it's limit 10<br /> <br /> The value has reached it's limit 11<br /> <br /> The value has reached it's limit 12<br /> <br /> The value has reached it's limit 13<br /> <br /> The value has reached it's limit 14<br /> <br /> The value has reached it's limit 15<br /> <br /> The value has reached it's limit 16<br /> <br /> The value has reached it's limit 17<br /> <br /> The value has reached it's limit 18<br /> <br /> The value has reached it's limit 19<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The output will consist of numbers '''10''' through '''19'''.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| <br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Now you should be able to create your own '''break '''construct.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 9<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| &lt;nowiki&gt;&lt;&lt;Pause&gt;&gt;&lt;/nowiki&gt;<br /> <br /> This brings us to the end of this Spoken Tutorial.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 10<br /> <br /> Summary<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Let's summarize.<br /> <br /> In this tutorial we have learnt to use<br /> <br /> * '''while''' loop<br /> * '''until''' construct<br /> * '''redo'''<br /> * '''break''' construct<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 11<br /> <br /> Assignment<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| As as assignment<br /> <br /> Write a '''Ruby '''program using<br /> <br /> * (I have yet to come up with an assignment)<br /> <br /> <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 12<br /> <br /> About the Spoken Tutorial Project<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Watch the video available at the following link.<br /> <br /> It summarizes the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it. <br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 13<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials<br /> <br /> Gives certificates to those who pass an online test<br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Slide 14<br /> <br /> Acknowledgements<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: <br /> <br /> spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| Previous slide<br /> | style=&quot;background-color:#ffffff;border-top:0.25pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.095cm;padding-right:0.095cm;&quot;| This [http://www.ruby-software.com/ i]s Anjana Nair signing off. Thank you<br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/File:While_and_until_loops_outline.txt 2013-06-17T05:10:11Z

<p>Anjana: </p> <hr /> <div></div>

Anjana https://script.spoken-tutorial.org/index.php/Ruby/C3/for-and-each-Looping-Statements/English 2013-04-18T07:17:39Z

<p>Anjana: Created page with ''''Title of script''': '''Looping Statements''' '''Author: Anjana Nair''' '''Keywords: for, each, loop, Ruby, video tutorial''' {| style=&quot;border-spacing:0;&quot; | style=&quot;border…'</p> <hr /> <div>'''Title of script''': '''Looping Statements'''<br /> <br /> '''Author: Anjana Nair'''<br /> <br /> <br /> '''Keywords: for, each, loop, Ruby, video tutorial'''<br /> <br /> <br /> <br /> {| style=&quot;border-spacing:0;&quot;<br /> | style=&quot;border-top:1pt solid #000000;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| &lt;center&gt;'''Visual Cue'''&lt;/center&gt;<br /> | style=&quot;border:1pt solid #000000;padding:0.097cm;&quot;| &lt;center&gt;'''Narration'''&lt;/center&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 1<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Welcome to the tutorial on '''for '''and '''each Loops''' in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 2<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In this tutorial we will learn<br /> <br /> * Meaning of the term “loop”<br /> * The different kinds of loops in '''Ruby'''<br /> * Usage of “'''for'''” loop and<br /> * Usage of “'''each'''” looping construct<br /> * <br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 3<br /> <br /> System Requirements<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Here we are using<br /> <br /> * '''Ubuntu''' version 12.04<br /> * '''Ruby''' 1.9.3<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 4<br /> <br /> Pre-requisites<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| To follow this tutorial, you must have '''Internet''' Connection.<br /> <br /> <br /> You must also have knowledge of '''Linux''' commands, '''Terminal''' and '''Text-editor.'''<br /> <br /> <br /> If not, for relevant tutorials, please visit our website.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now let me explain what is referred to as a “'''loop'''” in '''Ruby'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 5<br /> <br /> What is a loop?<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| A '''loop '''is a command or set of commands that are executed a fixed number of times.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 6<br /> <br /> Looping statements<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| '''Ruby''' has the following main looping statements.<br /> <br /> * '''for '''<br /> * '''each'''<br /> * '''while'''<br /> * '''until '''<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In this tutorial we will learn how to use the '''for''' and '''each''' looping constructs.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to gedit <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Click on “'''dash-home'''” and type '''gedit''' to invoke the editor.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to terminal<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Similarly, click on “'''dash-home'''” and select '''Terminal''' to open the '''terminal'''.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type mkdir ttt and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In the '''terminal,''' type “'''mkdir ttt'''”.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type cd ttt and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Then “'''cd'''” into that directory.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type mkdir ruby-tutorial and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Then type “'''mkdir ruby-tutorial'''”, <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type cd ruby-tutorial and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| And then “'''cd''' '''ruby-tutorial'''”.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type mkdir looping-statements and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Then type “'''mkdir looping-statements'''” <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Type cd looping-statements and press Enter <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| And then “'''cd looping-statements'''”<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now we have created the requisite folders. <br /> <br /> <br /> Let's move ahead.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 7<br /> <br /> “for” loop<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The syntax of the “'''for'''” loop in '''Ruby''' is as follows:<br /> <br /> <br /> '''for “variable” in “a collection of objects”'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us try to understand it with an example. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to gedit where you have already opened the file “for-loop.rb” with the '''for loop '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit''' as shown in the basic level '''Ruby '''tutorials.<br /> <br /> <br /> And name it “'''for-loop.rb'''”<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| I already have a working example of the “'''for”''' loop. <br /> <br /> You can type the code as we go through this example.<br /> <br /> <br /> Pause the tutorial while you do this.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| I have declared a “'''for”''' loop in this example.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight (1..20)<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| We have a set of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for i in (1..20)”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| We declare a variable called “'''i'''” within the “'''for”''' loop.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The variable '''“i” '''gets initialised to the first element in the set of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The “'''for'''” loop declaration causes the code to iterate over each element in the set 1 to 20. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “puts”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The “'''puts'''” method declared within the “'''for'''” loop is responsible for generating the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the terminal and type <br /> <br /> ruby for-loop.rb<br /> <br /> <br /> Point to the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now open the '''terminal''' and type <br /> <br /> “'''ruby for-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Analyzing the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The output will be an '''array''' of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In this example, we declared a “'''for'''” loop for an inclusive range.<br /> <br /> It included all numbers from 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Next we shall look at implementing the “'''for'''” loop for a non-inclusive range.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch back to the same file.<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Let's get back to the same file we were looking at.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Continue to type the next part of the code.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for i in (1...20)”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Non-inclusive means it will not include the last element in the collection of objects.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Here a “'''for'''” loop is implemented for a non-inclusive range of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| You will notice shortly that the number 20 will not be printed in the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the 3 dots only<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The last digit does not get included when you have 3 dots between numbers.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the terminal and type <br /> <br /> ruby for-loop.rb<br /> <br /> <br /> Point to the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| '''No'''w open the terminal and type “'''ruby for-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Analyzing the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The output will still be an array of numbers but will not include the number 20.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now, you should be capable enough to write your own “'''for'''” loop.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 8<br /> <br /> “each” loop<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The syntax of the “'''each'''” loop in '''Ruby '''is as follows:<br /> <br /> <br /> '''“a collection of objects”.each do |item|'''<br /> <br /> '''ruby code'''<br /> <br /> '''end'''<br /> <br /> <br /> Let us try to understand it with an example. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to gedit where you have already opened the file “each-loop.rb” with the '''each loop '''code typed inside.<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Create a new file in '''gedit''' as shown in the basic level '''Ruby''' tutorials.<br /> <br /> <br /> And name it “'''each-loop.rb'''”<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| I already have a working example of the “'''each”''' loop. <br /> <br /> <br /> You can type the code as we go through this example.<br /> <br /> <br /> Pause the tutorial while you do this.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| I have declared an “'''each'''” loop in this example.<br /> <br /> We have a set of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for i in (1..20)”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| We declare a variable called “'''i'''” within the “'''each'''” loop.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The “'''i'''” variable gets initialised to the first element in the set of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The '''“each”''' loop declaration causes the code to iterate over each element in the set 1 to 20. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “puts”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The “'''puts'''” method declared within the “'''each'''” loop is responsible for generating the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the terminal and type “'''ruby each-loop.rb'''” <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now open the '''terminal''' and type “'''ruby each-loop.rb'''” <br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Analyzing the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The output will be an array of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In the above example we declared an “'''each'''” loop for an inclusive range.<br /> <br /> <br /> It included all numbers from 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Next we shall look at implementing the “'''each'''” loop for a non-inclusive range.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch back to gedit<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Let's get back to the same file we were looking at.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Continue to type the next part of the code.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for i in (1...20)”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Non-inclusive means it will not include the last element in the collection of objects.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Here a “'''each'''” loop is implemented for a non-inclusive range of numbers 1 to 20.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Continue the highlight<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| You will notice shortly that the number 20 will not be printed in the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight the 3 dots only<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The last digit does not get included when you have 3 dots between numbers.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Switch to the terminal and type <br /> <br /> ruby each-loop.rb<br /> <br /> <br /> Point to the output<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| '''No'''w open the terminal and type “'''ruby for-loop.rb'''”<br /> <br /> <br /> and see the output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Now you should be capable enough to write your own “'''each'''” loop.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 9<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| How would we determine which looping contruct to choose?<br /> <br /> Let us try to recall the “'''for'''” loop construct.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Open “for-loop.rb”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In the first example, we iterated over a set of numbers 1 to 20 using “'''for'''”.<br /> <br /> <br /> Execute “ruby for-loop.rb” in your terminal and see the output.<br /> <br /> <br /> Now look at the code in '''gedit.'''<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Highlight “for number in (1..20)”<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| When you invoke the “'''for'''” loop, Ruby is actually calling the “'''each'''” method behind the scenes.<br /> <br /> <br /> And calling “'''each'''” or '''“for”''' will generate the same output.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Since the call to “'''for'''” in turn calls “each”, it is preferable to use the “'''each'''” loop instead.<br /> <br /> &lt;nowiki&gt;&lt;Pause&gt;&lt;/nowiki&gt;<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 10<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| &lt;nowiki&gt;&lt;&lt;Pause&gt;&gt;&lt;/nowiki&gt;<br /> <br /> This brings us to the end of this Spoken Tutorial.<br /> <br /> Let's summarize.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 11<br /> <br /> Summary<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| In this tutorial we have learnt<br /> <br /> * Usage of “'''for'''” loop<br /> * Usage of “'''each'''” construct<br /> * Reasoning behind using “'''each'''” instead of “'''for'''” <br /> * Examples of using the above looping constructs<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 12<br /> <br /> Assignment<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| As as assignment <br /> <br /> Write a ruby program using <br /> <br /> * the appropriate loop construct<br /> * to create an output of even numbers<br /> * from a set of numbers, say 1 to 20<br /> <br /> <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 13<br /> <br /> About the Spoken Tutorial Project<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Watch the video available at the following link.<br /> <br /> It summarises the Spoken Tutorial project.<br /> <br /> If you do not have good bandwidth, you can download and watch it. <br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 14<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| The Spoken Tutorial Project Team :<br /> <br /> <br /> Conducts workshops using spoken tutorials <br /> <br /> Gives certificates to those who pass an online test <br /> <br /> For more details, please write to<br /> <br /> contact at spoken hyphen tutorial dot org<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 15<br /> <br /> Acknowledgements<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| Spoken Tutorial Project is a part of the Talk to a Teacher project.<br /> <br /> It is supported by the National Mission on Education through ICT, MHRD, Government of India.<br /> <br /> More information on this Mission is available at: <br /> <br /> spoken hyphen tutorial dot org slash NMEICT hyphen Intro.<br /> <br /> |-<br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;&quot;| Slide 16<br /> <br /> About the contributor<br /> <br /> <br /> <br /> | style=&quot;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;&quot;| * This tutorial has been contributed by Ruby Software Pvt. Ltd<br /> * http://www.ruby-software.com<br /> * Thank you<br /> <br /> <br /> <br /> |}</div>

Anjana https://script.spoken-tutorial.org/index.php/File:Looping-statements-for-each-final.odt 2013-04-18T05:31:51Z

<p>Anjana: </p> <hr /> <div></div>

Anjana