Difference between revisions of "C-and-C++/C4/Function-Call/English-timed"
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Revision as of 10:04, 24 March 2014
| 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 |
| 06.58 | Conducts workshops using spoken tutorials |
| 07.01 | Gives certificates to those who pass an online test |
| 07.05 | For more details, please write to, contact@spoken-tutorial.org |
| 07.11 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 07.15 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 07.23 | More information on this Mission is available at the link shown below |
| 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
