C-and-C++/C4/Function-Call/English-timed

Time	Narration
00.01	Welcome to the spoken tutorial on Function calls in C and C++
00.07	In this tutorial we will learn about type of function calls namely
00.13	call by value.
00.14	call by reference.
00.16	We will do this through an example.
00.19	To record this tutorial, I am using Ubuntu Operating system version 11.10
00.26	gcc and g++ Compiler version 4.6.1
00.31	Let us start with the introduction to functions call by value
00.35	It is a method of passing arguments to the function.
00.40	When we pass a variable by value it makes a copy of the variable.
00.45	Before passing to the function.
00.48	Changes made to the arguments inside the function will remain in the function.
00.54	It will not be affected outside the function.
00.58	Let us see a program on function call by value.
01.02	I have already typed the program on the editor. I will just open it.
01.08	Please note our filename is callbyval.c.
01.13	In this program we will calculate the cube of a number. Let me explain the code now.
01.19	This is our header file
01.21	Here we have function cube having an argument as int x.
01.27	In this function we calculate the cube of x and return the value of x.
01.33	This is our main function.
01.36	Here we give the value of n as 8. n is an integer variable
01.43	Then we call the function cube.
01.45	And print the value of n and the cube of n.
01.49	And this is our return statement.
01.52	Now let us execute the program.
01.54	open the terminal window by pressing ' Ctrl, Alt and T keys simultaneously on your keyboard.
02.02	To compile , type gcc space callbyval.c space hyphen o space val. Press Enter
02.12	Now type dot slash val.Press Enter
02.16	The output is displayed as Cube of 8 is 512.
02.23	Now we will see function call by reference.
02.26	Let us go back to our slides.
02.29	It is another method of passing arguments to the function.
02.33	This method copies the address of the argument instead of the value.
02.39	Changes made to the arguments inside a function can affect them outside.
02.45	In this we need to declare the arguments as pointer type.
02.50	Let us see an example on function call by reference.
02.54	Note that our filename is callbyref.c
02.59	This is our header file as stdio.h
03.03	Then we have function swap
03.06	This function will exchange the values of the variables.
03.10	Value of a will be stored in value of b and vice-versa.
03.15	You can see that the arguments passed in the function are pointer type.
03.21	Here we have declared an integer variable t.
03.25	First value of a is stored in t.
03.28	Then value of b is stored in a.
03.32	And then value of t is stored in b
03.37	Like this the values are exchanged.
03.40	This is our main function.
03.42	Here we have declared two integer variables as i and j .
03.49	Then we take the values of i and j as user inputs.
03.53	Ampersand i and Ampersand j will give the memory address of i and j.
03.59	First we print the values before swapping.
04.04	Then we call the function swap
04.06	And then we print the values after swapping.
04.10	And this is our return statement.
04.13	Now let us execute the program
04.16	Switch back to our terminal
04.19	To compile type gcc space callbyref dot c space hyphen o space ref. Press Enter
04.29	Now type dot slash ref. Press Enter
04.33	We see, enter the values I will enter as 6 and 4
04.40	The output is displayed as,before swapping 6 and 4
04.44	After swapping 4 and 6
04.48	Now let us see how to execute the same program in C++
04.53	I have the code, lets go through it.
04.57	This is the second program function callbyreference .
05.01	Note that our filename is callbyref.cpp
05.06	Let us go through the code
05.08	This is our header file as iostream
05.12	Here we are using the std namespace
05.16	The function declaration is same in C++.
05.19	In this we pass the arguments as ampersand x and ampersand y.
05.25	This will give the memory address of x and y.
05.29	Then we swap the values.
05.32	Rest of the code is similar to our C code.
05.36	The printf' statement is replaced by cout and the scanf statement is replaced by cin
05.44	Now let us execute the program. Come back to our terminal
05.48	To compile type; g++ space callbyref.cpp space hyphen o space ref1, press Enter
06.00	Now Type dot slash ref1, Press Enter
06.05	Here it is displayed as:
06.07	Enter values of a and b
06.10	I will enter as 4 and 3
06.13	The output is displayed
06.15	Before swapping a and b 4 and 3
06.19	After swapping a and b 3 and 4
06.23	This brings us to the end of this tutorial.
06.26	Let us go back to our slides.
06.30	Let us summarize, In this tutorial we learn't:
06.32	Function call by value.
06.34	And Function call by reference.
06.37	As an assignment
06.38	Write a similar program to calculate the cube of a number.
06.42	Using call by value in C++.
06.46	Watch the video available at the link shown below
06.49	It summarizes the Spoken Tutorial project
06.52	If you do not have good bandwidth, you can download and watch it
06.56	The Spoken Tutorial Project Team
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07.27	This is Ashwini Patil from IIT Bombay signing off
07.31	Thank You for joining.

Contributors and Content Editors

Kavita salve, Krupali, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha