Ruby/C2/Control-Statements/Kannada

Time	Narration
00:01	'Ruby' ಯಲ್ಲಿ, 'Control Statements' ಎಂಬ 'Spoken Tutorial' ಗೆ ನಿಮಗೆ ಸ್ವಾಗತ.
00:06	ಈ ಟ್ಯುಟೋರಿಯಲ್ ನಲ್ಲಿ ನಾವು:
00:08	* 'if' ಸ್ಟೇಟ್ಮೆಂಟ್
00:09	* 'elsif' ಸ್ಟೇಟ್ಮೆಂಟ್
00:11	* 'else' ಸ್ಟೇಟ್ಮೆಂಟ್
00:12	* 'case' ಸ್ಟೇಟ್ಮೆಂಟ್ ಗಳನ್ನು ಬಳಸಲು ಕಲಿಯುವೆವು.
00:14	ಇಲ್ಲಿ ನಾವು:
00:15	* Ubuntu ಆವೃತ್ತಿ 12.04
00:18	* Ruby 1.9.3 ಇವುಗಳನ್ನು ಬಳಸುತ್ತಿದ್ದೇವೆ.
00:21	To follow this tutorial, you must have Internet connection. ಈ ಟ್ಯುಟೋರಿಯಲ್ ಅನ್ನು ಅನುಸರಿಸಲು, ನೀವು 'ಇಂಟರ್ನೆಟ್'ನ ಸಂಪರ್ಕವನ್ನು ಪಡೆದಿರಬೇಕು.
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
00:59	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 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”
02:19	ruby code
02:20	else
02:21	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.
03:27	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
03:55	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	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
06:29	when “value 2”
06:30	ruby code
06:31	else
06:32	ruby code
06:34	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.
09:08	In this tutorial, we have learnt to use:
09:10	* if statement
09:12	* else construct
09:13	* if-elsif and
09:15	* case statements.
09:17	As an assignment-
09:18	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.

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Outline: Control Statements in Ruby

   What are control statements
   Syntax for
       if statement
       if..else statement
       if..elsif statement
       Examples on it
   Ternary Operator
   Syntax for case statement and example on it
   Comparison between if..elsif and case statement

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Contributors and Content Editors

NaveenBhat, Sandhya.np14