C-and-C++/C2/If-And-Else-If-statement/English-timed

Time	Narration
00:02	Welcome to the spoken tutorial on Conditional statements in C and C++.
00:08	In this tutorial we will learn:
00:11	*How to execute a single statement
00:14	*How to execute group of statements.
00:16	We will do this through examples.
00:19	We will also see some common errors and their solutions.
00:25	To record this tutorial, I am using Ubuntu Operating system version 11.10.
00:31	gcc and g++ Compiler version 4.6.1.
00:38	Let us start with the introduction to conditional statements.
00:43	A statement in a program controls the flow of program execution.
00:49	It helps to make decision on what code is to be executed.
00:55	We can check the conditions, whether true or false.
01:00	We can execute a single statement or a group of statements.
01:07	Let us understand the flow of if statements.
01:13	Here, if the condition is true then statement 1 will be executed.
01:20	If the condition is false then statement 2 will be executed.
01:29	Now we will see the flow of else if statement.
01:32	Here, if condition 1 is true then statement 1 will be executed.
01:41	If condition 1 is false then it will check for another condition that is condition 2.
01:49	If condition 2 is true then statement 3 will be executed.
01:54	And If condition 2 is false then statement 2 will be executed.
02:02	Now Let us move on to our program.
02:06	I have already typed the code on the editor.
02:09	So, let me open it.
02:13	Note that our file name is ifstmt.c.
02:18	In this program we will calculate the sum of two numbers and will check a few conditions.
02:26	Let me explain the code now.
02:30	This is our header file.
02:34	This is our main() function.
02:38	Here we have declared three integer variables a, b and sum.
02:46	Here we are asking for user input.
02:49	User will enter the values of a and b.
02:52	The values will be stored in variable a and variable b.
02:58	The scanf() function reads data from the console.
03:02	It then stores the result in the given variable.
03:06	The format specifier in the scanf() helps to know the type of data.
03:10	Like here we have %d, it denotes that we are dealing with integer data type.
03:18	Here we add the values of a and b.
03:22	We will store the result in sum.
03:25	Then we print the result.
03:29	This is our if statement.
03:30	Here, we check the condition whether sum is greater than 20.
03:36	If the condition is true, then we print Sum is greater than 20.
03:42	Now let me comment out these lines.
03:48	This is our return statement.
03:51	Now click on Save.
03:53	First we will see the execution of if statement.
03:58	Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
04:09	To compile, type gcc space ifstmt dot c space -o space if and press Enter.
04:20	To execute, type ./if (dot slash if). Press Enter.
04:26	It is displayed as
04:27	Enter the values of a and b.
04:31	I will give the values as 10 and 12.
04:38	The output is displayed as Sum of a and b is 22. Sum is greater than 20.
04:45	Now come back to our program.
04:48	We will check another condition.
04:52	Let me remove the comment from here.
04:56	I will give the comment here.
05:00	Now click on Save.
05:03	This is our else-if statement.
05:05	Here, we check another condition whether Sum is greater than 10.
05:11	If the condition is true then we print 'Sum is greater than 10 and less than 20'.
05:18	Now come back to our terminal.
05:20	Let us compile as before.
05:23	Let us execute as before.
05:26	It is displayed as
05:28	Enter the value of a and b.
05:30	I will give the values as 10 and 2.
05:35	The output is displayed as: Sum of a and b is 12.
05:38	Sum is greater than 10 and less than 20.
05:42	Let me clear the prompt.
05:44	Now come back to our program.
05:48	I will remove the comment from here and here. Now click on Save.
05:56	If both the above conditions are false then we print 'Sum is less than 10'.
06:04	This is our else statement.
06:07	Now let us execute and see. Come back to our terminal.
06:11	Let us compile as before. Let us execute as before.
06:18	Here it is displayed as
06:19	Enter the value of a and b.
06:22	I will give the values as 3 and 5.
06:27	The output is displayed as sum of a and b is 8.
06:31	Sum is less than 10.
06:34	Now we will see some common errors which we can come across.
06:38	Come back to our program.
06:41	Suppose, here at the end of if statement I will type a semicolon (;).
06:47	Let us see what will happen. Click on Save.
06:50	Let us execute. Come back to our terminal.
06:53	Let us compile as before.
06:56	We see an error: 'else' without a previous 'if'
07:02	Come back to our program. It is a syntax error.
07:07	if statement will never terminate with a semicolon.
07:10	And the else if statement will never work without an if.
07:16	Let us fix the error. Delete the semicolon (;) here.
07:22	Now Click on Save.
07:25	Let us execute. Come back to the terminal.
07:29	Let us compile as before. Let us execute as before.
07:35	Enter the value of a and b.
07:37	I will give the values as 3 and 6.
07:43	The output is displayed as
07:45	Sum of a and b is 9. Sum is less than 10.
07:52	NOW WE WILL SEE HOW TO EXECUTE THE SAME PROGRAM IN C++.
07:57	Come back to our program.
07:59	I will change a few things here.
08:03	Press Shift, Ctrl and S keys simultaneously on your keyboard.
08:11	Now save the file with an extension dot cpp and click on Save.
08:20	We will change the header file as iostream.
08:26	Let us include the using statement here.
08:30	Now click on the Search for and replace text option.
08:35	Let us replace the printf statement with the cout statement.
08:40	Click on Replace all and click on Close.
08:46	Now delete the closing brackets here.
08:49	Replace the scanf() statement with the cin statement.
08:54	Type cin and two closing angle brackets >>.
09:00	As we use cin >> function to read a line in C++.
09:05	Now delete the format specifiers.
09:09	Delete the comma and ampersand &.
09:12	Delete the comma here and type two closing angle brackets.
09:17	Again delete the ampersandand the closing brackets. Now click on Save.
09:25	Here delete the closing bracket and the comma.
09:31	Now delete the 'backslash n' and 'format specifier'. '
09:37	Now type two opening brackets.
09:42	Again type two opening angle brackets and within the double quotes type backslash n “\n”.
09:49	Here also we will delete the closing bracket.
09:53	Now again delete the closing bracket here and here.
09:59	Now click on Save.
10:02	Let us execute.
10:04	Come back to the terminal. Let me clear the prompt.
10:10	To compile, type g++ space ifstmt.cpp space -o space if1
10:20	Here we have 'if1' because we don't want to overwrite the output parameter if for the file 'ifstmt.c'.
10:31	Now Press 'Enter'.
10:32	To execute type ./if1 (dot slash if1) and press Enter.
10:39	Enter the value of a and b. I will give the values as 20 and 10.
10:48	The output is displayed as Sum of a and b is 30
10:52	Sum is greater than 20
10:56	This brings us to the end of this tutorial.
10:59	Now come back to our slides.
11:02	Let us summarize.
11:04	In this tutorial we learned 'if' statement eg. if(condition),
11:11	And 'else if' statement eg. else if(condition).
11:17	As an assignment,
11:18	Write a program to check 'a' is greater than 'b' or less than 'b'.
11:24	Hint: use 'if' statement.
11:28	Write another program to check which value is greater 'a', 'b' or 'c'.
11:34	Hint: use 'else-if' statement.
11:38	Watch the video available at the link shown below.
11:41	It summarizes the Spoken Tutorial project.
11:44	If you do not have good bandwidth, you can download and watch it.
11:48	The Spoken Tutorial Project Team,
11:50	Conducts workshops using spoken tutorials.
11:54	Gives certificates to those who pass an online test.
11:57	For more details, please write to, contact @ spoken hyphen tutorial dot org.
12:04	Spoken Tutorial Project is a part of the Talk to a Teacher project.
12:09	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
12:15	More information on this Mission is available at the link shown below.
12:20	This is Ashwini Patil from IIT BombayA Thank You for watching.

Contributors and Content Editors

Ashwini, Devraj, Kavita salve, Krupali, PoojaMoolya, Priyacst, Sakinashaikh, Sandhya.np14, Sneha