Difference between revisions of "Ruby/C3/while-and-until-Looping-Statements/English-timed"

| Welcome to the tutorial on '''while''' and '''until loops''' in Ruby.  

| In this tutorial we will learn to use-  

| '''while loop '''

 

|'''until loop '''

| '''redo'''

 

|and '''break'''   

|We are using  

 

|  00:14

| ''' Ubuntu''' version 12.04  

|''' Ruby '''1.9.3  

|To follow this tutorial, you must have ''' Internet''' Connection.   

|Then to ''' ruby hyphen tutorial''' and '''looping hyphen statements''' directory.   

|''' ruby code '''

 

|'''end'''  

| Create a new file in '''gedit''' as shown in the basic level ''' Ruby''' tutorials.   

| Name it ''' while hyphen loop dot rb '''

|I have a working example of the ''' while loop'''.  

|Now let us switch to the terminal and type  ''' gedit space while hyphen loop dot rb space &''' (ampersand)

| First, I declared a local variable '''i''' and initialized it with value 0.  

 

|Then I declare a ''' while loop. '''

| This loop will execute as long as the variable ''' i''' is greater than -10.  

 

| The '''puts''' method is declared within the ''' while''' loop will display the output.  

| After the output is displayed, we decrement the value of i by 1.  

|'''i''' will adopt this decremented value before the next iteration.  

 

|The variable ''' i ''' gets decremented in every iteration.   

|This goes on till '''i''' reaches the value -10,

|  At this point the '''while condition''' fails.  

| Now, let us switch to the '''terminal''' and type '''ruby space while hyphen loop dot rb''' and see the output.  

 

| You should now be able to write your own '''while''' loop in '''Ruby. '''

|''' ruby code '''

 

| 02:48

| '''end'''

| Now let us switch to a '''terminal''' and type ''' gedit space until hyphen loop dot rb space &''' (ampersand)

|You can pause the tutorial, and type the code as we go through it.  

|We had declared a local variable ''' i''' and initialized it to 0.  

|This loop will execute as long as the variable '''i''' is greater than -10.  

|The '''puts''' method will display the output.  

| After the output is displayed, value of '''i''' is decremented by 1.   

|'''i''' will adopt this decremented value before the next iteration.  

| The variable '''i''' gets decremented during every iteration.  

|  This goes on till '''i''' reaches the value -11.  

|At this point the '''until condition''' fails.   

|Now switch to the ''' terminal''' and type ''' ruby space until hyphen loop dot rb''' and see the output.  

| The syntax for '''redo''' in ''' Ruby''' is as follows:  

|''' a collection of objects.each do item '''

| '''a conditional statement '''

|'''ruby code '''

 

|'''redo'''

|'''end''' conditional

 

| 04:30

| '''end''' loop  

|Now let us switch to the terminal and type '''gedit space redo hyphen loop dot rb space &'''(ampersand )

| You can pause the tutorial, and type the code as we go through it.  

| Then, we define an ''' if''' conditional statement.  

 

| It will enter the inner conditional ''' if''' conditional block only if the value of i is equal to 20.   

|The '''puts''' method declared within the '''each''' loop displays the output.  

| Once the program enters the ''' if''' conditional block, it will first print the output.  

|Then it will execute '''redo. '''

|It will do so without checking the loop condition.  

|Our condition being ''' if i == 20. '''

| The result will be an infinite loop, since the value of '''i''' will not change from 20.   

|Let's switch to the '''terminal''' and type '''ruby space redo hyphen loop dot rb'''

|and see the output.  

 

|The output will consist of an infinite loop that never ends.  

|Press '''Ctrl + C''' to terminate the infinite loop  

|The syntax for the '''break''' statement in '''Ruby''' is -   

|'''a looping statement '''

| '''a conditional statement '''

|'''break '''

|'''ruby code'''

 

|'''end loop '''

|Now let us switch to the '''terminal''' and type '''gedit space break hyphen loop dot rb space ampersand.'''

 

|You can pause the tutorial, and type the code as we go through this example.  

 

|The '''puts''' method here will display the output for numbers 11 to 19.  

|Once the value becomes 20, the program enters the conditional '''if''' block.  

|At this point, it will encounter the '''break''' statement and break out of the loop.  

|Now open the '''terminal''' and type  

|Now you should be able to create your own '''break''' construct.  

|In this tutorial we have learnt to use  

 

|'''while''' loop  

 

|'''until''' construct  

|'''redo'''

 

|'''break''' construct  

|As as assignment  

|Consider a range of numbers 100 to 115(inclusive) represented as Fahrenheit.

|against the given range of numbers

|To display the output: ''' “The temperature has reached a certain degree Celcius and has become unbearable”'''

|when the temperature in Celcius is above 32 degree Celcius

|It summarises the Spoken Tutorial project.

|  The Spoken Tutorial Project Team :

|Conducts workshops using spoken tutorials  

|Gives certificates to those who pass an online test  

|For more details, please write to contact@spoken-tutorial.org

|  Spoken Tutorial Project is a part of the Talk to a Teacher project.

|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro

| This is Anjana Nair signing off. Thank you