Difference between revisions of "Ruby/C2/Control-Statements/English-timed"

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{| border=1
 
{| border=1
 
|| '''Time'''
 
|| '''Time'''
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|-
 
|-
 
|  00:01
 
|  00:01
| Welcome to the spoken tutorial on Control Statements in ''' Ruby.'''  
+
| Welcome to the '''spoken tutorial''' on '''Control Statements''' in '''Ruby.'''  
  
 
|-
 
|-
 
| 00:06
 
| 00:06
| In this tutorial we will learn to use
+
| In this tutorial, we will learn to use:
  
 
|-
 
|-
 
| 00:08
 
| 00:08
| ''' if statement '''
+
| ''''if'''' statement ,  ''''elsif'''' statement
 
+
|-
+
| 00:09
+
|''' elsif statement '''
+
  
 
|-
 
|-
 
| 00:11
 
| 00:11
| ''' else'''
+
| ''''else''', ''''case'''' statements.
 
+
|-
+
|  00:12
+
|''' case statements'''
+
  
 
|-
 
|-
 
|  00:14
 
|  00:14
|Here we are using  
+
|Here we are using: '''Ubuntu''' version '''12.04'''
 
+
|-
+
|  00:15
+
''' Ubuntu''' version 12.04  
+
  
 
|-
 
|-
 
| 00:18
 
| 00:18
|''' Ruby '''1.9.3  
+
|''' Ruby 1.9.3'''.
  
 
|-
 
|-
 
| 00:21
 
| 00:21
|To follow this tutorial, you must have ''' Internet''' Connection.   
+
|To follow this tutorial, you must have ''' Internet''' connection.   
 
    
 
    
 
 
|-
 
|-
 
|  00:24
 
|  00:24
| You must also have knowledge of '''Linux''' commands, ''' Terminal''' and ''' Text-editor.'''
+
| You must also have knowledge of '''Linux''' commands, ''' Terminal''' and ''' Text-editor.'''
 
+
 
+
  
 
|-
 
|-
Line 58: Line 41:
 
|-
 
|-
 
|  00:34
 
|  00:34
|  Before we begin, recall that we had created ''' “ttt” ''' directory earlier.  
+
|  Before we begin, recall that we had created '''“ttt”''' directory earlier.  
  
 
|-
 
|-
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|-
 
|-
 
| 00:41
 
| 00:41
|Then to ''' ruby hyphen tutorial'''   ''' control hyphen statements'''  
+
|Then to '''ruby hyphen tutorial''' '''control hyphen statements'''.
  
 
|-
 
|-
Line 74: Line 57:
 
|-
 
|-
 
| 00:52
 
| 00:52
| The syntax of the ''' if statement''' in '''Ruby''' is as follows:  
+
| The syntax of the ''''if' statement''' in Ruby is as follows:  
  
 
|-
 
|-
 
| 00:56
 
| 00:56
|''' if “condition” '''
+
|'''if “condition” '''
  
 
|-
 
|-
 
|  00:58
 
|  00:58
|  ''' ruby code'''  
+
|  ''' ruby code'''. '''end'''  
 
+
|-
+
| 00:59
+
|'''end'''  
+
  
 
|-
 
|-
Line 94: Line 73:
 
|-
 
|-
 
| 01:03
 
| 01:03
|Create a new file in ''' gedit''' as shown in the basic level '''Ruby''' tutorials.   
+
|Create a new file in ''' gedit''' as shown in the basic level '''Ruby tutorials'''.   
  
 
|-
 
|-
 
| 01:08
 
| 01:08
|Name it ''' if hyphen statement dot rb'''
+
|Name it '''if hyphen statement dot rb'''.
  
 
|-
 
|-
 
| 01:12
 
| 01:12
|I have a working example of the ''' if statement.'''  
+
|I have a working example of the ''' if''' statement.
 
+
  
 
|-
 
|-
 
|  01:15
 
|  01:15
|  You can pause the tutorial, and type the code as we go through it.  
+
|  You can pause the tutorial and type the code as we go through it.  
  
 
|-
 
|-
 
|  01:19
 
|  01:19
|I have declared an ''' if statement''' in this example.  
+
|I have declared an '''if statement''' in this example.  
  
 
|-
 
|-
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|-
 
|-
 
| 01:31
 
| 01:31
| Then I declare an ''' if''' statement.  
+
| Then I declare an '''if''' statement.  
  
 
|-
 
|-
Line 127: Line 105:
 
|-
 
|-
 
| 01:39
 
| 01:39
|The '''if statement''' will check the value of ''' my_num''' is greater than 0.  
+
|The '''if''' statement will check if the value of ''' my_num''' is greater than 0.  
  
 
|-
 
|-
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|-
 
|-
 
| 01:47
 
| 01:47
|Now, let us switch to the '''terminal''' and type  
+
|Now, let us switch to the '''terminal''' and type:
  
 
|-
 
|-
 
|  01:51
 
|  01:51
|  ''' ruby space if hyphen statement dot rb'''  
+
|  '''ruby space if hyphen statement dot rb'''.
  
 
|-
 
|-
Line 151: Line 129:
 
|-
 
|-
 
|  02:07
 
|  02:07
|You should now be able to write your own ''' if statement''' in '''Ruby.'''
+
|You should now be able to write your own ''' 'if' statement''' in Ruby.  
  
 
|-
 
|-
 
|  02:12
 
|  02:12
| Let's look at the ''' if-else statement''' next.  
+
| Let's look at the ''' 'if-else' statement''' next.  
  
 
|-
 
|-
 
|  02:16
 
|  02:16
 
| The syntax for using '''else''' is:  
 
| The syntax for using '''else''' is:  
 
  
 
|-
 
|-
 
| 02:18
 
| 02:18
|''' if “condition” '''
+
|''' if “condition” ''', ''' ruby code'''  
 
+
|-
+
|  02:19
+
| ''' ruby code'''  
+
  
 
|-
 
|-
 
| 02:20
 
| 02:20
|'''else'''
+
|'''else''', '''ruby code '''
 
+
|-
+
| 02:21
+
| '''ruby code '''
+
  
 
|-
 
|-
Line 188: Line 157:
 
|-
 
|-
 
| 02:26
 
| 02:26
|Create a new file in ''' gedit''' as shown in the basic level ''' Ruby''' tutorials.   
+
|Create a new file in ''' gedit''' as shown in the basic level ''' Ruby tutorials'''.   
 
+
  
 
|-
 
|-
 
| 02:30
 
| 02:30
|Name it ''' if hyphen else hyphen statement dot rb'''
+
|Name it '''if hyphen else hyphen statement dot rb'''.
  
 
|-
 
|-
 
| 02:37
 
| 02:37
|I have a working example of the ''' if-else statement.'''  
+
|I have a working example of the ''' 'if-else' statement.'''  
  
 
|-
 
|-
 
|  02:40
 
|  02:40
|  You can pause the tutorial, and type the code as we go through it.  
+
|  You can pause the tutorial and type the code as we go through it.  
  
 
|-
 
|-
 
| 02:44
 
| 02:44
|I have declared an ''' if-else statement''' in this example.  
+
|I have declared an '''if-else statement''' in this example.  
  
 
|-
 
|-
Line 217: Line 185:
 
|-
 
|-
 
| 02:58
 
| 02:58
|The '''if''' statement will check if the value of ''' my_num''' is greater than 0.  
+
|The ''''if'''' statement will check if the value of 'my_num' is greater than 0.  
 
+
  
 
|-
 
|-
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|-
 
|-
 
|  03:13
 
|  03:13
|  Now, let us switch to the '''terminal''' and type  
+
|  Now, let us switch to the '''terminal''' and type:
  
 
|-
 
|-
 
|  03:18
 
|  03:18
 
|'''ruby space if hyphen else hyphen statement dot rb'''  
 
|'''ruby space if hyphen else hyphen statement dot rb'''  
 
  
 
|-
 
|-
 
|  03:26
 
|  03:26
|  and see the output.
+
|  and see the output.The output will display ''' “The value of my_num is lesser than 0”.'''  
 
+
|-
+
| 03:27
+
|The output will display ''' “The value of my_num is lesser than 0”.'''  
+
  
 
|-
 
|-
Line 255: Line 217:
 
|-
 
|-
 
|  03:35
 
|  03:35
| You should now be able to write your own ''' if-else statement''' in '''Ruby.'''
+
| You should now be able to write your own ''' if-else statement''' in Ruby.  
  
 
|-
 
|-
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| 03:48
 
| 03:48
 
|''' if “condition” '''  ''' ruby code'''  
 
|''' if “condition” '''  ''' ruby code'''  
 
  
 
|-
 
|-
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| ''' elsif “condition” ''' ''' ruby code'''  
 
| ''' elsif “condition” ''' ''' ruby code'''  
 
   
 
   
 
 
|-
 
|-
 
| 03:52
 
| 03:52
Line 281: Line 241:
 
|-
 
|-
 
| 03:54
 
| 03:54
|'''end '''
+
|'''end '''. Let us look at an example.  
 
+
|-
+
| 03:55
+
|Let us look at an example.  
+
  
 
|-
 
|-
 
|  03:58
 
|  03:58
| Create a new file in '''gedit''' as shown in the basic level '''Ruby''' tutorials.  
+
| Create a new file in '''gedit''' as shown in the basic level '''Ruby tutorials'''.  
 
+
  
 
|-
 
|-
 
| 04:01
 
| 04:01
|Name it ''' if hyphen elsif hyphen statement dot rb'''
+
|Name it ''' if hyphen elsif hyphen statement dot rb'''.
 
+
  
 
|-
 
|-
 
|  04:07
 
|  04:07
| I have a working example of the ''' if-elsif- statement.'''  
+
| I have a working example of the '''if-elsif''' statement.
 
+
  
 
|-
 
|-
 
|  04:10
 
|  04:10
|You can pause the tutorial, and type the code as we go through it.  
+
|You can pause the tutorial and type the code as we go through it.  
  
 
|-
 
|-
Line 312: Line 265:
 
|-
 
|-
 
| 04:19
 
| 04:19
|Here also, I have declare a local variable '''my_num''' and assign the value -1 to it.  
+
|Here also, I have declared a local variable '''my_num''' and assigned the value -1 to it.  
  
 
|-
 
|-
Line 324: Line 277:
 
|-
 
|-
 
| 04:32
 
| 04:32
| If it is, it will print out the specified string.  
+
| If it is, it will print out the specified '''string'''.  
 
+
  
 
|-
 
|-
 
| 04:35
 
| 04:35
| If this is not ''' true''' , it will go into the '''elsif''' section.  
+
| If this is not ''' true''', it will go into the '''elsif''' section.  
  
 
|-
 
|-
Line 337: Line 289:
 
|-
 
|-
 
| 04:43
 
| 04:43
|If it is true, it will print out the string that is specified there.  
+
|If it is true, it will print out the '''string''' that is specified there.  
  
 
|-
 
|-
 
| 04:46
 
| 04:46
| The value of '''my_num''' is neither greater than 0 nor equal to -1 it will go into the '''else''' section.  
+
| If the value of '''my_num''' is neither greater than 0 nor equal to -1, it will go into the '''else''' section.  
 
+
  
 
|-
 
|-
 
| 04:54
 
| 04:54
|But since the value of '''my_num = -1''' it will not proceed to the else block.  
+
|But, since the value of '''my_num = -1''' it will not proceed to the '''else''' block.  
  
 
|-
 
|-
 
| 05:00
 
| 05:00
|And it will exit the ''' conditional statement.'''  
+
|And, it will exit the ''' conditional statement.'''  
  
 
|-
 
|-
 
| 05:03
 
| 05:03
|Now, let us switch to the ''' terminal''' and type  
+
|Now, let us switch to the ''' terminal''' and type:
  
 
|-
 
|-
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|-
 
|-
 
| 05:29
 
| 05:29
|Let's save the code and execute it on the terminal.  
+
|Let's '''save''' the code and '''execute''' it on the '''terminal'''.  
  
 
|-
 
|-
 
| 05:35
 
| 05:35
|So, now it fulfills the if condition and the specified string is printed.  
+
|So, now it fulfills the '''if''' condition and the specified '''string''' is printed.  
  
 
|-
 
|-
 
|  05:42
 
|  05:42
| The value of ''' my_num''' is greater than 0
+
| '''"The value of ''' my_num''' is greater than 0"'''.
  
 
|-
 
|-
 
| 05:45
 
| 05:45
|Let's go back to our file and change the value of  ''' my_num''' to -5
+
|Let's go back to our file and change the value of  ''' my_num''' to -5.
  
 
|-
 
|-
 
| 05:50
 
| 05:50
|Lets save the code and execute it on the terminal
+
|Let's '''save''' the code and execute it on the terminal.
  
 
|-
 
|-
 
|  05:55
 
|  05:55
|  In this case it fulfills the ''' else''' condition and the puts statement within the else block gets executed.  
+
|  In this case, it fulfills the ''' else''' condition and the '''puts''' statement within the '''else''' block gets executed.  
 
   
 
   
 
|-
 
|-
 
| 06:03
 
| 06:03
|You should now be able to write your own ''' if- elsif''' statement in ''' Ruby. '''
+
|You should now be able to write your own ''' if-elsif''' statement in Ruby.  
  
 
|-
 
|-
 
| 06:08
 
| 06:08
|Let us look at the ''' case statement''' next.  
+
|Let us look at the ''''case' statement''' next.  
  
 
|-
 
|-
 
| 06:12
 
| 06:12
| The ''' case statement''' is a ''' control flow statement''' based on a particular selection.  
+
| The ''''case' statement''' is a ''' control flow statement''' based on a particular selection.  
  
 
|-
 
|-
 
| 06:17
 
| 06:17
| Let us look at the syntax of the '''case statement''' in order to understand this statement.  
+
| Let us look at the syntax of the ''''case' statement''' in order to understand this statement.  
  
 
|-
 
|-
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|-
 
|-
 
| 06:24
 
| 06:24
|''' case variable'''
+
|'''case''' variable
  
 
|-
 
|-
 
| 06:26
 
| 06:26
|''' when “value 1” '''
+
| when “value 1”  
  
 
|-
 
|-
 
| 06:28
 
| 06:28
|'''ruby code '''
+
|'''ruby code '''when “value 2” '''ruby code '''
 
+
|-
+
| 06:29
+
|''' when “value 2” '''
+
 
+
|-
+
| 06:30
+
| '''ruby code '''
+
  
 
|-
 
|-
 
| 06:31
 
| 06:31
| '''else'''
+
| '''else''' ''' ruby code '''. '''end'''.
 
+
|-
+
| 06:32
+
| ''' ruby code '''
+
 
+
 
+
|-
+
| 06:34
+
|'''end'''
+
  
 
|-
 
|-
Line 455: Line 389:
 
|-
 
|-
 
| 06:37
 
| 06:37
|Create a new file in ''' gedit''' as shown in the basic level '''Ruby''' tutorials.  
+
|Create a new file in ''' gedit''' as shown in the basic level '''Ruby tutorials'''.  
  
 
|-
 
|-
 
| 06:41
 
| 06:41
|Name it '''case hyphen statement dot rb'''
+
|Name it '''case hyphen statement dot rb'''.
  
 
|-
 
|-
 
| 06:44
 
| 06:44
|I have a working example of the ''' case statement.'''
+
|I have a working example of the 'case' statement.  
  
 
|-
 
|-
 
| 06:48
 
| 06:48
|You can pause the tutorial, and type the code as we go through it.  
+
|You can pause the tutorial and type the code as we go through it.  
  
 
|-
 
|-
 
| 06:52
 
| 06:52
|I have declared an ''' case statement''' in this example.  
+
|I have declared a '''case''' statement in this example.  
  
 
|-
 
|-
 
| 06:55
 
| 06:55
|Here I have a '''print statement,''' which will print a question on the terminal.  
+
|Here, I have a print statement which will print a question on the terminal.  
  
 
|-
 
|-
 
| 07:01
 
| 07:01
|Then I call a '''gets''', which will accept a single line of data from the standard input.  
+
|Then I call a '''gets''' which will accept a single line of data from the '''standard input'''.  
  
 
|-
 
|-
Line 488: Line 422:
 
| 07:15
 
| 07:15
 
|I assign the result to a variable named '''domain.'''
 
|I assign the result to a variable named '''domain.'''
 
  
 
|-
 
|-
 
| 07:18
 
| 07:18
|Then I declare a case statement.  
+
|Then I declare a '''case''' statement.  
  
 
|-
 
|-
 
| 07:22
 
| 07:22
|Within that I declare a '''when statement '''.  
+
|Within that, I declare a '''when''' statement .  
 
+
  
 
|-
 
|-
 
| 07:25
 
| 07:25
|This checks whether the specified string matches value of ''' domain.'''  
+
|This checks whether the specified '''string''' matches the value of ''' domain'''.
  
 
|-
 
|-
 
| 07:30
 
| 07:30
|First it checks whether the value of '''domain''' is ''' “UP”. '''
+
|First, it checks whether the value of '''domain''' is '''“UP”.'''
  
 
|-
 
|-
 
| 07:34
 
| 07:34
|If it is so, it will print out ''' “Uttar Pradesh” ''' and exit the '''case statement.'''  
+
|If it is so, it will print out ''' “Uttar Pradesh” ''' and exit the '''case''' statement.
  
 
|-
 
|-
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|-
 
|-
 
| 07:53
 
| 07:53
|At this point it will encounter the ''' else statement'''  
+
|At this point, it will encounter the ''' else''' statement
  
 
|-
 
|-
 
| 07:56
 
| 07:56
|as none of the above conditions were true.  
+
|as none of the above conditions were '''true'''.  
  
 
|-
 
|-
 
| 07:59
 
| 07:59
|It will subsequently execute the ''' ruby code''' that follows the '''else''' declaration.  
+
|It will subsequently execute the ruby code that follows the '''else''' declaration.  
  
 
|-
 
|-
Line 541: Line 473:
 
|-
 
|-
 
| 08:07
 
| 08:07
|Now, save the file, switch to the ''' terminal''' and type  
+
|Now, save the file. Switch to the ''' terminal''' and type:
 
+
  
 
|-
 
|-
Line 562: Line 493:
 
|-
 
|-
 
| 08:28
 
| 08:28
|Next execute the ''' Ruby''' file again, like before.  
+
|Next, execute the Ruby file again, like before.  
 
+
  
 
|-
 
|-
 
| 08:31
 
| 08:31
|This time at the prompt type ''' “KL”''' and see the output.  
+
|This time, at the prompt, type: ''' “KL”''' and see the output.  
  
 
|-
 
|-
Line 575: Line 505:
 
|-
 
|-
 
| 08:38
 
| 08:38
|Next execute the file one more time.  
+
|Next, execute the file one more time.  
  
 
|-
 
|-
 
| 08:41
 
| 08:41
|This time at the prompt type in ''' “TN”''' and see the output.  
+
|This time, at the prompt, type in ''' “TN”''' and see the output.  
  
 
|-
 
|-
Line 591: Line 521:
 
|-
 
|-
 
| 08:58
 
| 08:58
|You should now be able to write your own ''' case-statements''' in '''Ruby. '''
+
|You should now be able to write your own ''' case-statements''' in Ruby.  
  
 
|-
 
|-
 
| 09:03
 
| 09:03
 
|This brings us to the end of this Spoken Tutorial.  
 
|This brings us to the end of this Spoken Tutorial.  
 
  
 
|-
 
|-
 
| 09:07
 
| 09:07
|Let's summarize.  
+
|Let's summarize. In this tutorial, we have learnt to use:
 
+
|-
+
| 09:08
+
|In this tutorial we have learnt to use  
+
 
+
  
 
|-
 
|-
 
| 09:10
 
| 09:10
|''' if statement'''  
+
| '''if''' statement
  
 
|-
 
|-
 
| 09:12
 
| 09:12
|''' else''' construct  
+
| ''' else''' construct, '''if-elsif''' and  
 
+
|-
+
| 09:13
+
|'''if-elsif''' and  
+
  
 
|-
 
|-
 
| 09:15
 
| 09:15
|''' case statements'''  
+
| ''' case statements'''.
  
 
|-
 
|-
 
| 09:17
 
| 09:17
|As an assignment :
+
|As an assignment- write a '''Ruby''' program  
 
+
|-
+
| 09:18
+
|Write a '''Ruby''' program :
+
 
+
  
 
|-
 
|-
 
| 09:20
 
| 09:20
|that prompts a user to enter a number  
+
|that prompts a user to enter a number,
 
+
  
 
|-
 
|-
Line 643: Line 557:
 
|-
 
|-
 
| 09:26
 
| 09:26
|to check if the number is a multiple of 2  
+
|to check if the number is a multiple of 2.
  
 
|-
 
|-
 
|09:29
 
|09:29
|if it is, then print “The number entered is a multiple of 2”  
+
|If it is, then print: “The number entered is a multiple of 2”.
  
 
|-
 
|-
 
| 09:35
 
| 09:35
|if not, it should check if it is a multiple of 3  
+
|If not, it should check- if it is a multiple of 3.
  
 
|-
 
|-
 
| 09:38
 
| 09:38
|if it is, then print “The number entered is a multiple of 3”  
+
|If it is, then print: “The number entered is a multiple of 3”.
  
 
|-
 
|-
 
| 09:43
 
| 09:43
|if not, it should check if it a multiple of 4  
+
|If not, it should check if it is a multiple of 4.
  
 
|-
 
|-
 
| 09:47
 
| 09:47
|if it is, then print “The number entered is a multiple of 4”  
+
|If it is, then print: “The number entered is a multiple of 4”.
  
 
|-
 
|-
 
| 09:51
 
| 09:51
|if not, it should print “The number is not a multple of 2, 3 or 4”  
+
|If not, it should print: “The number is not a multiple of 2, 3 or 4”.
  
 
|-
 
|-
Line 675: Line 589:
 
|-
 
|-
 
| 10:00
 
| 10:00
|It summarises the Spoken Tutorial project.
+
|It summarizes the Spoken Tutorial project.
  
 
|-
 
|-
Line 683: Line 597:
 
|-
 
|-
 
|  10:07
 
|  10:07
| The Spoken Tutorial Project Team :
+
| The Spoken Tutorial project team:
  
 
|-   
 
|-   
 
| 10:09
 
| 10:09
|Conducts workshops using spoken tutorials  
+
| Conducts workshops using spoken tutorials.
  
 
|-
 
|-
 
|10:13
 
|10:13
|Gives certificates to those who pass an online test  
+
| Gives certificates to those who pass an online test.
  
 
|-
 
|-
 
| 10:16
 
| 10:16
|For more details, please write to contact@spoken-tutorial.org
+
|For more details, please write to: contact@spoken-tutorial.org
  
 
|-
 
|-
 
|  10:21
 
|  10:21
| Spoken Tutorial Project is a part of the Talk to a Teacher project.
+
| '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project.
  
 
|-
 
|-
Line 707: Line 621:
 
|-
 
|-
 
| 10:32
 
| 10:32
|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro
+
|More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
  
 
|-
 
|-
 
| 10:41
 
| 10:41
|This is Anjani Nair signing off. Thanks for watching.
+
|This is Anjani Nair, signing off. Thanks for watching.
 
+
 
+
 
+
  
 
|}
 
|}

Latest revision as of 12:19, 10 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on Control Statements in Ruby.
00:06 In this tutorial, we will learn to use:
00:08 'if' statement , 'elsif' statement
00:11 'else, 'case' statements.
00:14 Here we are using: Ubuntu version 12.04
00:18 Ruby 1.9.3.
00:21 To follow this tutorial, you must have Internet connection.
00:24 You must also have knowledge of Linux commands, Terminal and Text-editor.
00:30 If not, for relevant tutorials, please visit our website.
00:34 Before we begin, recall that we had created “ttt” directory earlier.
00:38 Let's go to that directory.
00:41 Then to ruby hyphen tutorial control hyphen statements.
00:47 Now that we are in that folder, let’s move ahead.
00:52 The syntax of the 'if' statement in Ruby is as follows:
00:56 if “condition”
00:58 ruby code. end
01:01 Let us look at an example.
01:03 Create a new file in gedit as shown in the basic level Ruby tutorials.
01:08 Name it if hyphen statement dot rb.
01:12 I have a working example of the if statement.
01:15 You can pause the tutorial and type the code as we go through it.
01:19 I have declared an if statement in this example.
01:23 First, I declare a local variable my_num and assign the value 2345 to it.
01:31 Then I declare an if statement.
01:34 The puts method declared within the if statement will display the output.
01:39 The if statement will check if the value of my_num is greater than 0.
01:43 If it is, it will print out the specified string.
01:47 Now, let us switch to the terminal and type:
01:51 ruby space if hyphen statement dot rb.
01:57 The output will display “The value of my_num is greater than 0”.
02:02 This output proves that the if condition returned true.
02:07 You should now be able to write your own 'if' statement in Ruby.
02:12 Let's look at the 'if-else' statement next.
02:16 The syntax for using else is:
02:18 if “condition” , ruby code
02:20 else, ruby code
02:22 end
02:24 Let us look at an example.
02:26 Create a new file in gedit as shown in the basic level Ruby tutorials.
02:30 Name it if hyphen else hyphen statement dot rb.
02:37 I have a working example of the 'if-else' statement.
02:40 You can pause the tutorial and type the code as we go through it.
02:44 I have declared an if-else statement in this example.
02:48 First I declare a local variable my_num and assign the value of -1 to it.
02:55 Then I declare an if statement.
02:58 The 'if' statement will check if the value of 'my_num' is greater than 0.
03:03 If it is, it will print out the specified string.
03:06 If not, it will go to the else statement.
03:10 And it will print out the string that is specified there.
03:13 Now, let us switch to the terminal and type:
03:18 ruby space if hyphen else hyphen statement dot rb
03:26 and see the output.The output will display “The value of my_num is lesser than 0”.
03:32 This shows that the else statement was executed.
03:35 You should now be able to write your own if-else statement in Ruby.
03:41 Let's look at the if-elsif statement next.
03:45 The syntax for using elsif is:
03:48 if “condition” ruby code
03:50 elsif “condition” ruby code
03:52 else ruby code
03:54 end . Let us look at an example.
03:58 Create a new file in gedit as shown in the basic level Ruby tutorials.
04:01 Name it if hyphen elsif hyphen statement dot rb.
04:07 I have a working example of the if-elsif statement.
04:10 You can pause the tutorial and type the code as we go through it.
04:14 I have declared an if-elsif statement in this example.
04:19 Here also, I have declared a local variable my_num and assigned the value -1 to it.
04:25 Then I declare an if statement.
04:28 The if statement will check if the value of my_num is greater than 0.
04:32 If it is, it will print out the specified string.
04:35 If this is not true, it will go into the elsif section.
04:39 It will now check if the value of my_num is equal to -1.
04:43 If it is true, it will print out the string that is specified there.
04:46 If the value of my_num is neither greater than 0 nor equal to -1, it will go into the else section.
04:54 But, since the value of my_num = -1 it will not proceed to the else block.
05:00 And, it will exit the conditional statement.
05:03 Now, let us switch to the terminal and type:
05:07 ruby space if hyphen elsif hyphen statement dot rb
05:15 and see the output.
05:17 The output will display “The value of my_num is -1 and is lesser than 0”.
05:23 Let's go back to our file and change the value of my_num to 5.
05:29 Let's save the code and execute it on the terminal.
05:35 So, now it fulfills the if condition and the specified string is printed.
05:42 "The value of my_num is greater than 0".
05:45 Let's go back to our file and change the value of my_num to -5.
05:50 Let's save the code and execute it on the terminal.
05:55 In this case, it fulfills the else condition and the puts statement within the else block gets executed.
06:03 You should now be able to write your own if-elsif statement in Ruby.
06:08 Let us look at the 'case' statement next.
06:12 The 'case' statement is a control flow statement based on a particular selection.
06:17 Let us look at the syntax of the 'case' statement in order to understand this statement.
06:22 The syntax for using case is:
06:24 case variable
06:26 when “value 1”
06:28 ruby code . when “value 2” ruby code
06:31 else ruby code . end.
06:35 Let us look at an example.
06:37 Create a new file in gedit as shown in the basic level Ruby tutorials.
06:41 Name it case hyphen statement dot rb.
06:44 I have a working example of the 'case' statement.
06:48 You can pause the tutorial and type the code as we go through it.
06:52 I have declared a case statement in this example.
06:55 Here, I have a print statement which will print a question on the terminal.
07:01 Then I call a gets which will accept a single line of data from the standard input.
07:09 Then I strip the input data of any new line characters using chomp.
07:15 I assign the result to a variable named domain.
07:18 Then I declare a case statement.
07:22 Within that, I declare a when statement .
07:25 This checks whether the specified string matches the value of domain.
07:30 First, it checks whether the value of domain is “UP”.
07:34 If it is so, it will print out “Uttar Pradesh” and exit the case statement.
07:39 If domain is not “UP”, it checks whether the value of domain is “MP”.
07:44 If it is so, it will print out “Madhya Pradesh” and so on.
07:48 It will continue checking the value of domain if no match was found so far.
07:53 At this point, it will encounter the else statement
07:56 as none of the above conditions were true.
07:59 It will subsequently execute the ruby code that follows the else declaration.
08:03 It will print “Unknown” as per our example.
08:07 Now, save the file. Switch to the terminal and type:
08:11 ruby space case hyphen statement dot rb.
08:18 “Enter the state you live in:” will be displayed on the terminal.
08:22 Type in “UP” and see the output.
08:25 The output will display “Uttar Pradesh”.
08:28 Next, execute the Ruby file again, like before.
08:31 This time, at the prompt, type: “KL” and see the output.
08:36 It will print “Kerala”.
08:38 Next, execute the file one more time.
08:41 This time, at the prompt, type in “TN” and see the output.
08:47 It will print “Unknown”.
08:50 This is because none of the cases were satisfied. So, the default else statement is executed.
08:58 You should now be able to write your own case-statements in Ruby.
09:03 This brings us to the end of this Spoken Tutorial.
09:07 Let's summarize. In this tutorial, we have learnt to use:
09:10 if statement
09:12 else construct, if-elsif and
09:15 case statements.
09:17 As an assignment- write a Ruby program
09:20 that prompts a user to enter a number,
09:23 then use the appropriate control-statement
09:26 to check if the number is a multiple of 2.
09:29 If it is, then print: “The number entered is a multiple of 2”.
09:35 If not, it should check- if it is a multiple of 3.
09:38 If it is, then print: “The number entered is a multiple of 3”.
09:43 If not, it should check if it is a multiple of 4.
09:47 If it is, then print: “The number entered is a multiple of 4”.
09:51 If not, it should print: “The number is not a multiple of 2, 3 or 4”.
09:56 Watch the video available at the following link.
10:00 It summarizes the Spoken Tutorial project.
10:03 If you do not have good bandwidth, you can download and watch it.
10:07 The Spoken Tutorial project team:
10:09 Conducts workshops using spoken tutorials.
10:13 Gives certificates to those who pass an online test.
10:16 For more details, please write to: contact@spoken-tutorial.org
10:21 Spoken Tutorial project is a part of the Talk to a Teacher project.
10:26 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:32 More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
10:41 This is Anjani Nair, signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14