Difference between revisions of "C-and-C++/C4/Understanding-Pointers/English-timed"
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Revision as of 15:43, 23 June 2014
| Time | Narration |
| 00:01 | Welcome to the spoken tutorial on Pointers in C and C++ |
| 00:06 | In this tutorial we will learn, |
| 00:08 | Pointers. |
| 00:10 | To create Pointers. |
| 00:12 | And operations on Pointers. |
| 00:14 | We will do this with the help of an example |
| 00:18 | To record this tutorial I am using Ubuntu operating system version 11.10 |
| 00:25 | gcc and g++ compiler version 4.6.1 on Ubuntu |
| 00:31 | Let us start with an introduction to pointers |
| 00:34 | Pointers point to the locations in memory. |
| 00.38 | Pointers store the memory address. |
| 00:41 | It also gives value stored at that address. |
| 00:45 | Now, let us see an example on pointers |
| 00:48 | Note that our file name is pointers_demo.c |
| 00:54 | Let us go through the code now |
| 00:56 | This is our header file as stdio.h |
| 01:00 | This is our main function |
| 01:03 | Here we have long integer num assigned value 10. |
| 01:09 | Then we have declared a pointer ptr. |
| 01:12 | Asterisk sign is used to declare a pointer. |
| 01:16 | This pointer can point to type long int. |
| 01:20 | In the printf statement ampersand is used for retrieving memory address of the variable. |
| 01:28 | So ampersand num will give the memory address of num. |
| 01:33 | This statement will print the address of the variable num. |
| 01:37 | Over here ptr stores the address of num. |
| 01:41 | This statement will print the address of ptr.
|
| 01:45 | Sizeof function will give the size of ptr. |
| 01:49 | This is will give the value of ptr. |
| 01:51 | That is the memory address of num. |
| 01:54 | And here asterisk ptr will give the value at the address. |
| 01:59 | So using asterisk will not give the memory address. |
| 02:03 | Instead it will give the value. |
| 02:06 | %ld is a format specifier for the long int |
| 02:10 | Now, let us execute the program |
| 02:13 | Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard |
| 02:21 | To compile type gcc space pointers underscore demo dot c space hyphen o space point
|
| 02:32 | Press Enter |
| 02:34 | Type dot slash point. Press Enter |
| 02:39 | The output is displayed |
| 02:42 | We see that the num address and ptr value is same. |
| 02:48 | Where as memory address of num and ptr are different. |
| 02:53 | Then the size of pointer is 8 bytes. |
| 02:57 | Also the value pointed by ptr is 10 which was assigned to num. |
| 03:03 | Now let us see the same program in C++. |
| 03:07 | Note that our file name is pointer underscore demo.cpp |
| 03:13 | Here we have few changes like the header file as iostream |
| 03:19 | Then we are using the std namespace |
| 03:23 | And we have the cout function in place of printf function |
| 03:28 | Rest all the things are similar |
| 03:30 | Let us execute the program. Come back to our terminal. |
| 03:34 | To compile type g++ space pointers_demo.cpp space hyphen o space point1, press Enter |
| 03:50 | Type dot slash point1, press Enter |
| 03:55 | We can see that the output is similar to our C program |
| 04:00 | This brings us to the end of this tutorial. |
| 04:03 | Come back to our slide |
| 04:05 | Let us summarize |
| 04:06 | In this tutorial, we learnt |
| 04:08 | About the pointer. |
| 04:10 | To create a pointer. |
| 04:12 | And operation on pointer. |
| 04:14 | As an assignment, write a C and C++ program, |
| 04:18 | To declare a variable and pointer. |
| 04:21 | Store the address of variable in the pointer. |
| 04:24 | And print the value of the pointer. |
| 04:27 | Watch the video available at the link shown below |
| 04:30 | It summarizes the Spoken Tutorial project |
| 04:33 | If you do not have good bandwidth, you can download and watch it |
| 04:37 | The Spoken Tutorial Project Team |
| 04:39 | Conducts workshops using spoken tutorials |
| 04:43 | Gives certificates to those who pass an online test |
| 04:47 | For more details, please write to, contact@spoken-tutorial.org |
| 04:53 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 04:58 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 05:06 | More information on this Mission is available at the link shown below |
| 05:10 | This is Ashwini Patil from IIT Bombay signing off |
| 05:14 | Thank You for joining. |
Contributors and Content Editors
Kavita salve, Krupali, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha
