Ashwini at 06:16, 8 May 2013

2013-05-08T06:16:32Z

Ashwini: Created page with ''''Title of script''': Friend function in C++ '''Author: '''Ashwini Patil '''Keywords: friend function, C++, Video tutorial.''' {| style="border-spacing:0;" | style="backgro…'

2013-05-06T07:48:33Z

Created page with ''''Title of script''': Friend function in C++ '''Author: '''Ashwini Patil '''Keywords: friend function, C++, Video tutorial.''' {| style="border-spacing:0;" | style="backgro…'

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'''Title of script''': Friend function in C++

'''Author: '''Ashwini Patil

'''Keywords: friend function, C++, Video tutorial.'''

{| style="border-spacing:0;"
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| style="background-color:#ffffff;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| <center>'''Narration'''</center>

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Welcome to the spoken tutorial on '''friend''' '''function '''in '''C++.'''

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| In this tutorial we will learn,

'''Friend function.'''

We will do this with the help of examples.

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'''Ubuntu OS '''version 11.10

'''g++ compiler '''v. 4.6.1

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| We know, the private data is not accessible outside the class.

To access the private data we use '''friend function'''.

A friend function is not a member of the class.

The function can be invoked without using an object.

The argument passed in the friend function is used as its object.

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| style="background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Declaration of a friend function

'''friend return_type function_name( class_name object)'''

'''friend''' keyword is used to declare a friend function.

Then we give the '''return_type'''.

'''function_name''' is the name of the function.

Then we pass arguments as '''class_name''' and object of the class.

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Let us look at an example

In this program we will perform addition operation.

I have already typed the code on the editor.

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'''frnd.cpp'''
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Let me explain the code now.

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'''<nowiki>#include<iostream></nowiki>'''
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'''using namespace std;'''
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| This is the using statement.

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'''class frnd '''

'''{ '''

'''private: '''

'''int a,b; '''

'''public: '''

'''void input()'''
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Here we have declared a '''class frnd.'''

In this we have declared variables '''a''' and '''b '''as private.

And '''input''' as '''public''' member function.

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'''<nowiki>cout<<"Enter the value of a and b\n"; </nowiki>'''

'''cin>>a>>b;'''
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'''friend int compute(frnd f1);'''

'''};'''
| style="background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| This is our '''friend function '''as''' compute'''.

Here, we have passed arguments as '''class_name''' '''frnd '''and''' object '''of the''' class'''.

Then we close the class.

We can access the private members of class frnd using the friend function

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'''int compPlease make a mention of the compute method.'''ute(frnd f1)'''

'''return int(f1.a+f1.b);'''
| style="background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Here we have the compute method, In this we will perform addition operation.

Here we add the variables.

And return the value.

Here we access the private variables in non-member function using the '''object f1.'''

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'''int main() '''

'''{'''
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'''frnd f; '''

'''f.input(); '''

'''<nowiki>cout << "The result is: " << compute(f)<<"\n"; </nowiki>'''
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| In main function we create an '''object''' of class '''frnd''' as '''f.'''

We call the '''function input.'''

Then we call '''function compute '''and pass''' f '''as argument.

You can see that we have passed the argument as f in function compute.

This is done by using the method pass by value.

f is passed to the value of f1.

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'''return 0;'''
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| This is the return statement.

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Now Click on '''Save'''

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'''Ctrl, Alt and T '''keys simultaneously
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'''g++ frnd.cpp -o frnd'''

To execute

Type

'''./frnd'''
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'''g++ frnd.cpp -o frnd'''

To execute type

'''./frnd'''

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'''Output'''
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'''Enter the value of a and b'''

I will enter as:

'''8'''

'''4'''

The output is displayed as:

'''The result is: 12'''

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Summary
| style="background-color:#ffffff;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| In this tutorial we have seen

'''Friend function.'''

'''eg. friend int compute(frnd f1);'''

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Assignment
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| As an assignment,

Write a program to find out the square and cube of a number.

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About the Spoken Tutorial Project
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Watch the video available at the link shown

It summarizes the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Slide 10

Spoken Tutorial Workshops
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| 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

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Slide Number 11

Acknowledgement
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| Spoken Tutorial Project is a part of the Talk to a Teacher project

It is supported by the National Mission on Education through ICT, MHRD, Government of India

More information on this Mission is available at: [http://spoken-tutorial.org/NMEICT-Intro http://spoken-tutorial.org\NMEICT-Intro]

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| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:0.25pt solid #c0c0c0;border-left:1pt solid #000000;border-right:0.25pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"|
| style="background-color:#ffffff;border-top:0.25pt solid #c0c0c0;border-bottom:0.25pt solid #c0c0c0;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.018cm;padding-right:0.018cm;"| This is Ashwini Patil from IIT Bombay signing off

Thank You for joining.

|}

Advanced-C++/C2/Friend-Function/English - Revision history

Ashwini at 06:16, 8 May 2013

Ashwini: Created page with ''''Title of script''': Friend function in C++ '''Author: '''Ashwini Patil '''Keywords: friend function, C++, Video tutorial.''' {| style="border-spacing:0;" | style="backgro…'