Difference between revisions of "C-and-C++/C4/Function-Call/English-timed"

|Welcome to the spoken tutorial on '''Function calls in C and C++'''

|In this tutorial we will learn about type of function calls namely

|call by value.    

|To record this tutorial, I am using '''Ubuntu Operating system '''version 11.10

|'''gcc''' and '''g++''' Compiler version 4.6.1  

| Let us start with the introduction to '''functions call by value'''

| When we pass a variable by value it makes a copy of the variable.

|Before passing to the function.

|Let us see a program on function call by value.  

| Please note our filename is '''callbyval.c. '''

|In this program we will calculate the cube of a number. Let me explain the code now.  

|This is our '''header file'''

|Here we have function '''cube''' having an '''argument''' as '''int x. '''

|In this function we calculate the cube of '''x''' and return the value of '''x.  '''

|This is our '''main function.'''

|Here we give the value of '''n''' as '''8. n''' is an integer variable

|And print the value of '''n '''and the cube of n.

|And this is our return statement.  

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

|To compile , type '''gcc space callbyval.c space hyphen o space val. Press Enter'''

|Now type '''./val '''(dot slash val).Press '''Enter'''

|The output is displayed as '''Cube of 8 is 512.'''

|Now we will see function call by reference.  

|Note that our filename is '''callbyref.c'''

|This is our header file as '''stdio.h'''

|Then we have function '''swap'''

|Value of a will be stored in value of b and vice-versa.  

|First value of a is stored in t.

|Then value of b is stored in a.

| And then value of t is stored in b  

|This is our '''main''' function.  

|Here we have declared two integer variables as i and j .  

|Ampersand i and Ampersand j will give the memory address of i and j.

|First we print the values before swapping.  

|Then we call the function '''swap'''

|And this is our return statement.  

| Now let us execute the program  

| Switch back to our terminal  

|To compile type '''gcc space callbyref dot c space hyphen o space ref'''. Press Enter

|Now type '''dot slash ref'''. Press Enter

|We see, enter the values I will enter as 6 and 4

|The output is displayed as,before swapping 6 and 4

|After swapping 4 and 6

|Now let us see how to execute the same program in C++  

|Let us go through the code  

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

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

|The '''printf''' statement is replaced by cout and the scanf statement is replaced by cin   

|Now let us execute the program. Come back to our terminal  

|To compile type; '''g++ space callbyref.cpp space hyphen o space ref1''', press Enter

|Now Type '''dot slash ref1,''' Press Enter

|I will enter as 4 and 3

|The output is displayed  

|Let us summarize, In this tutorial we learn't:  

|As an assignment  

|Write a similar program to calculate the cube of a number.  

|Watch the video available at the link shown below

|It summarizes the Spoken Tutorial project  

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|The Spoken Tutorial Project Team  

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| This is Ashwini Patil from IIT Bombay signing off