Difference between revisions of "C-and-C++/C4/Understanding-Pointers/English-timed"
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| 01:20 | | 01:20 | ||
| − | |In the printf | + | |In the 'printf' statement, ampersand is used for retrieving memory address of the variable. |
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| 01:41 | | 01:41 | ||
|This statement will print the address of ptr. | |This statement will print the address of ptr. | ||
| − | |||
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|01:59 | |01:59 | ||
| − | |So using asterisk will not give the memory address. | + | |So, using asterisk will not give the memory address. |
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|02:06 | |02:06 | ||
| − | |%ld is a format specifier for the long int | + | |'''%ld''' is a format specifier for the long int. |
|- | |- | ||
|02:10 | |02:10 | ||
| − | |Now, let us execute the program | + | |Now, let us execute the program. |
|- | |- | ||
|02:13 | |02:13 | ||
| − | |Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard | + | |Open the terminal window by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously on your keyboard. |
|- | |- | ||
|02:21 | |02:21 | ||
| − | |To compile type '''gcc space pointers underscore demo dot c space hyphen o space point''' | + | |To compile, type '''gcc space pointers underscore demo dot c space hyphen o space point''' |
| − | + | ||
|- | |- | ||
|02:32 | |02:32 | ||
| − | |Press '''Enter''' | + | |Press '''Enter'''. |
|- | |- | ||
|02:34 | |02:34 | ||
| − | |Type '''dot slash point'''. Press '''Enter''' | + | |Type '''dot slash point'''. Press '''Enter'''. |
|- | |- | ||
|02:39 | |02:39 | ||
| − | |The output is displayed | + | |The output is displayed. |
|- | |- | ||
| 02:42 | | 02:42 | ||
| − | |We see that the num address and ptr value is same | + | |We see that the num address and ptr value is same |
|- | |- | ||
| 02:48 | | 02:48 | ||
| − | | | + | | where as memory address of num and ptr are different. |
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| 03:07 | | 03:07 | ||
| − | | Note that our file name is '''pointer underscore demo.cpp''' | + | | Note that our file name is '''pointer underscore demo.cpp'''. |
|- | |- | ||
| 03:13 | | 03:13 | ||
| − | | Here we have few changes like the header file as '''iostream''' | + | | Here we have few changes like the header file as '''iostream'''. |
|- | |- | ||
| 03:19 | | 03:19 | ||
| − | |Then we are using the '''std namespace''' | + | |Then we are using the '''std namespace'''. |
|- | |- | ||
| 03:23 | | 03:23 | ||
| − | |And we have the cout function in place of printf function | + | |And we have the '''cout''' function in place of printf() function. |
|- | |- | ||
| 03:28 | | 03:28 | ||
| − | |Rest all the things are similar | + | |Rest all the things are similar. |
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| 03:34 | | 03:34 | ||
| − | |To compile type '''g++ space pointers_demo.cpp space hyphen o space point1''', press Enter | + | |To compile, type '''g++ space pointers_demo.cpp space hyphen o space point1''', press Enter. |
|- | |- | ||
| 03:50 | | 03:50 | ||
| − | |Type '''dot slash point1''', press '''Enter''' | + | |Type '''dot slash point1''', press '''Enter'''. |
|- | |- | ||
| 03:55 | | 03:55 | ||
| − | | We can see that the output is similar to our C program | + | | We can see that the output is similar to our C program. |
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| 04:03 | | 04:03 | ||
| − | | Come back to our slide | + | | Come back to our slide. |
|- | |- | ||
| 04:05 | | 04:05 | ||
| − | |Let us summarize | + | |Let us summarize. |
|- | |- | ||
| 04:06 | | 04:06 | ||
| − | |In this tutorial, we learnt | + | |In this tutorial, we learnt: |
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| 04:14 | | 04:14 | ||
| − | |As an assignment, write a C and C++ program | + | |As an assignment, write a C and C++ program: |
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| 04:27 | | 04:27 | ||
| − | |Watch the video available at the link shown below | + | |Watch the video available at the link shown below. |
|- | |- | ||
| 04:30 | | 04:30 | ||
| − | |It summarizes the Spoken Tutorial project | + | |It summarizes the Spoken Tutorial project. |
|- | |- | ||
| 04:33 | | 04:33 | ||
| − | |If you do not have good bandwidth, you can download and watch it | + | |If you do not have good bandwidth, you can download and watch it. |
|- | |- | ||
| 04:37 | | 04:37 | ||
| − | |The Spoken Tutorial Project Team | + | |The Spoken Tutorial Project Team: |
|- | |- | ||
| 04:39 | | 04:39 | ||
| − | |Conducts workshops using spoken tutorials | + | |Conducts workshops using spoken tutorials. |
|- | |- | ||
|04:43 | |04:43 | ||
| − | |Gives certificates to those who pass an online test | + | |Gives certificates to those who pass an online test. |
|- | |- | ||
| 04:47 | | 04:47 | ||
| − | |For more details, please write to | + | |For more details, please write to contact@spoken-tutorial.org. |
|- | |- | ||
| 04:53 | | 04:53 | ||
| − | |Spoken Tutorial Project is a part of the Talk to a Teacher project | + | |Spoken Tutorial Project is a part of the Talk to a Teacher project. |
|- | |- | ||
| 04:58 | | 04:58 | ||
| − | |It is supported by the National Mission on Education through ICT, MHRD, Government of India | + | |It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
|- | |- | ||
| 05:06 | | 05:06 | ||
| − | |More information on this Mission is available at the link shown below | + | |More information on this Mission is available at the link shown below. |
|- | |- | ||
| 05:10 | | 05:10 | ||
| − | | This is Ashwini Patil from IIT Bombay signing off | + | | This is Ashwini Patil from IIT Bombay, signing off. |
|- | |- | ||
| 05:14 | | 05:14 | ||
|Thank You for joining. | |Thank You for joining. | ||
Revision as of 14:14, 12 February 2015
| 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 (&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 | Size of 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
