Difference between revisions of "C-and-C++/C4/Understanding-Pointers/English"
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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| System Requirement Slide 3 | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| System Requirement Slide 3 | ||
| − | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| | + | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To record this tutorial I am using |
Ubuntu OS version11.10 | Ubuntu OS version11.10 | ||
| Line 48: | Line 48: | ||
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|Now let us see an example on Pointers | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|Now let us see an example on Pointers | ||
| − | Note that our filename is ''' | + | Note that our filename is '''pointers_demo.c''' |
Let us go through the code now. | Let us go through the code now. | ||
| + | |||
This is our header file as '''stdio.h''' | This is our header file as '''stdio.h''' | ||
| + | |||
This is our main function. | This is our main function. | ||
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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| | ||
| − | Here we have a long integer num assigned value 10. | + | Here we have a '''long integer num''' assigned value '''10.''' |
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Instead it will give the value. | Instead it will give the value. | ||
| + | |||
%ld is the format specifier for long int. | %ld is the format specifier for long int. | ||
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| − | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type: gcc | + | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type: gcc pointers_demo.c -o point. |
./point | ./point | ||
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To compile type: | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To compile type: | ||
| − | gcc space | + | gcc space pointers_demo.c space -o space point. |
'''Press Enter''' | '''Press Enter''' | ||
./point | ./point | ||
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Where as memory address of num and ptr are different. | Where as memory address of num and ptr are different. | ||
| − | Then the size of pointer is 8 bytes. | + | Then the size of pointer is '''8 bytes.''' |
| − | Also the value pointed by ptr is 10, which was assigned to num. | + | Also the value pointed by '''ptr''' is 10, which was assigned to '''num.''' |
|- | |- | ||
| Line 133: | Line 136: | ||
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now let us see the same program in C++. | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now let us see the same program in C++. | ||
Note that the filename is '''pointers_demo.cpp''' | Note that the filename is '''pointers_demo.cpp''' | ||
| + | |||
Here we have a few changes. | Here we have a few changes. | ||
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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|To compile type: | | style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|To compile type: | ||
| − | g++ space | + | '''g++ space pointers_demo.cpp space -o space point1''' |
| + | |||
'''Press Enter''' | '''Press Enter''' | ||
| + | |||
| + | Type | ||
| + | |||
./point1 | ./point1 | ||
| + | |||
'''Press Enter''' | '''Press Enter''' | ||
Latest revision as of 16:25, 31 January 2014
Title of script: Pointer in C and C++
Author: Ashwini Patil
Keywords: Pointers, video tutorial()
| |
|
| Opening slide1 | Welcome to the spoken tutorial on Pointers in C and C++ |
| Learning objectives Slide 2 | In this tutorial we will learn
Pointers. To create Pointers. And operations on Pointer. We will do this with the help of an example. |
| System Requirement Slide 3 | To record this tutorial I am using
Ubuntu OS version11.10 gcc and g++ compiler version 4.6.1 on Ubuntu |
| What is a Pointer? | Let is start with an introduction to pointers.
Pointers point to the locations in memory. Pointers store the memory address. It also gives value stored at that address. |
| Switch to gedit Text Editor | Now let us see an example on Pointers
Note that our filename is pointers_demo.c Let us go through the code now. This is our header file as stdio.h This is our main function. |
|
Highlight num |
Here we have a long integer num assigned value 10. |
| Highlight *ptr | Then we have declared a pointer ptr.
Asterisk sign is used to declare a pointer. This pointer can point to type long int. |
| Highlight &num | In the printf statement ampersand is used for retrieving memory address of the variable.
So ampersand num will give the memory address of num. This statement will print the address of the variable num. |
| Highlight ptr=&num | Over here ptr stores the address of num. |
| Highlight &ptr | This statement will print the address of ptr. |
| Highlight sizeof(ptr) | Sizeof function will give the size of ptr. |
| Highlight ptr | This will give the value of ptr.
That is the memory address of num. |
| Highlight *ptr | And here asterisk ptr will give the value at the address.
So using asterik will not give the memory address. Instead it will give the value. %ld is the format specifier for long int. |
| Save, Compile and Run | Now let us execute the program.
Open the terminal by pressing Ctrl, Alt and T keys simultaneously on your keyboard. |
| Type: gcc pointers_demo.c -o point.
./point |
To compile type:
gcc space pointers_demo.c space -o space point. Press Enter ./point Press Enter
|
| Output | The output is displayed.
We see that the num address and ptr value is same. Where as memory address of num and ptr are different. Then the size of pointer is 8 bytes. Also the value pointed by ptr is 10, which was assigned to num. |
| Code in C++ | Now let us see the same program in C++.
Note that the filename is pointers_demo.cpp Here we have a few changes. |
| Highlight Code in C++ | Like the header file as iostream
Then we are using the std namespace
|
| Highlight Code in C++ | Here we have cout function in place of printf function.
Rest all the things are similar.
|
| On the terminal | Let us execute the program.
Come back to our terminal. |
| To compile type:
g++ space pointers_demo.cpp space -o space point1 Press Enter Type ./point1 Press Enter | |
| Output | We can see that the output is similar to our C program.
This brings us to the end of this tutorial. Come back to our slides. |
| Summary Slide | Let us summarize.
In this tutorial we have learnt. About the pointer. To create a pointer. Operation on pointer. |
| Assignment Slide | As an assignment
Write a C and C++ program, declare a variable and pointer. Store the address of variable in the pointer. Print the value of pointer. |
| Slide 8
About Slide |
To know more about the Spoken Tutorial Project
|
| Slide 9
About Slide
|
The Spoken Tutorial Project Team
|
| Slide 10
Acknowledgment |
Spoken Tutorial Project is a part of the Talk to a Teacher project
|
| We have come to the end of this tutorial.
Thanks for joining. This is Ritwik signing off. Jai Hind. |
