Advanced-C++/C2/Friend-Function/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on friend function in C++.
00:06	In this tutorial we will learn,
00:08	Friend function.
00:10	We will do this with the help of an example.
00:13	To record this tutorial, I am using
00:15	Ubuntu OS v. 11.10
00:19	g++ compiler v. 4.6.1
00:24	Let us start with the introduction to friend function.
00:27	We know, the private data is not accessible outside the class.
00:33	To access the private data we use friend function.
00:37	A friend function is not a member function of the class.
00:42	Friend function can be invoked without using an object.
00:46	The argument passed in the friend function is used as its object.
00:51	Let us see the declaration of a friend function.
00:55	friend keyword is used to declare a friend function.
00:59	Then we give the return_type.
01:02	function_name is the name of the function.
01:05	Then we pass arguments as class_name and object of the class.
01:11	Let us look at an example
01:13	I have already typed the code on the editor.
01:16	I will open it.
01:18	In this program we will perform addition operation.
01:22	Note that our filename is frnd.cpp
01:27	Let me explain the code now.
01:30	This is our header file as iostream.
01:34	Here we are using std namespace.
01:37	Then we have declared a class frnd.
01:41	In this we have declared variables a and b as private.
01:46	Here we have declared a function input as public
01:52	In this we take input from the user.
01:55	This is our friend function as compute.
01:58	Here, we have passed arguments as class_name frnd and object of the class f1.
02:06	Then we close the class.
02:08	Now we can access the private members of class frnd using the friend function.
02:16	Here we have used the compute function.
02:19	In this we will perform addition operation.
02:23	We add the variables a and b
02:26	And then return the value.
02:28	Here we access the private variables in non-member function using the object f1.
02:35	This is our main function.
02:38	In this we create an object of class frnd as f.
02:44	Then we call the function input using the object f.
02:48	And here we call function compute and pass f as argument.
02:54	You can see that we have passed the argument as f in function compute.
02:58	This is done by using the method pass by value.
03:03	f is passed to the value of f1.
03:06	And this is our return statement.
03:09	Now let us execute the program.
03:11	Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
03:20	Now type:
03:21	g++ space frnd dot cpp space hyphen o space frnd.Press Enter.
03:32	Type: dot slash frnd
03:36	Press Enter
03:38	Here it is displayed as: Enter the value of a and b
03:41	I will enter as: 8 and 4
03:46	The output is displayed as:
03:48	The result is: 12
03:51	This brings us to the end of this tutorial.
03:54	Let us move back to our slides.
03:56	Let us summarize:
03:57	In this tutorial we learned Friend function. eg. friend int compute class name frnd and object f1.
04:08	As an assignment, Write a program to find out the square and cube of a number.
04:14	Watch the video available at the link shown
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04:56	This is Ashwini Patil from IIT Bombay signing off Thank You for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14