Difference between revisions of "Advanced-C++/C2/Friend-Function/English-timed"

| Welcome to the '''spoken tutorial''' on '''Friend Function '''in '''C++.'''

| In this tutorial, we will learn

|  To record this tutorial, I am using:

|'''Ubuntu OS '''version '''11.10'''

|'''g++ compiler '''version '''4.6.1'''

| Let us start with an introduction to '''friend function.'''

| 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 function''' of the '''class'''.

| '''Friend function''' can be invoked without using an '''object'''.

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

|  Let us see the declaration of a '''friend function.'''

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

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

|  Let us look at an example.

| I have already typed the '''code''' on the '''editor'''.

| In this program, we will perform addition operation.

|  Note that our file-name is '''frnd.cpp'''.

| Let me explain the '''code''' now.

|  This is our '''header file''' as '''iostream.'''

|  Here we are using '''std namespace.'''

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

|Here we have declared a function '''input()''' as '''public'''.

|  In this, we take input from the user.

| This is our '''friend function '''as''' compute()'''.

| Here, we have passed '''arguments''' as '''class_name''' '''frnd '''and''' object '''of the''' class 'f1' '''.

| Then we close the '''class.'''

| Now, we can access the '''private members''' of '''class''' '''frnd''' using the '''friend function.'''

|  Here, we have used the '''compute()''' function.

| In this, we will perform addition operation.

| We add the variables 'a' and 'b'.

| And then return the '''value'''.

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

|  This is our '''main()''' function.

|  In this, we create an '''object''' of class '''frnd''' as '''f.'''

| Then we call the function '''input() '''using the''' object f.'''

|And here, we call function '''compute() '''and pass''' f '''as argument.  

| You can see that we have passed the '''argument''' as '''f''' in function '''compute()'''.

|  And this is our '''return''' statement.

|  Now, let us '''execute''' the program.

|  Open the '''terminal window''' by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously on your keyboard.

| '''g++ space frnd dot cpp space hyphen o space frnd'''. Press '''Enter'''.

| Type: '''dot slash frnd'''

| press '''Enter'''.

|  Here, it is displayed as:  '''Enter the value of a and b'''.

| I will enter as: '''8''' and '''4'''.

| '''The result is: 12'''.

| Let us move back to our '''slides'''.

|  Let us summarize.In this tutorial, we learned  '''Friend function.''' e.g. '''friend int compute class-name frnd''' and '''object 'f1' '''.

|  As an assignment,  write a program to find out the square and cube of a number.

|  Watch the video available at the link shown below.

| It summarizes the Spoken-Tutorial project.

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

|  The Spoken-Tutorial Project team: conducts workshops using spoken tutorials.

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|This is Ashwini Patil from IIT Bombay, signing off.Thank You for joining.