Difference between revisions of "C-and-C++/C4/Understanding-Pointers/English-timed"

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|Welcome to the spoken tutorial on '''Pointers in C and C++ '''
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|Welcome to the spoken tutorial on '''Pointers in C and C++ '''.
  
 
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|In this tutorial we will learn,    
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|In this tutorial we will learn:    
  
 
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|Pointers.
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|* Pointers  
  
 
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|To create Pointers.
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|* To create Pointers  
  
 
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|And operations on Pointers.  
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|* And operations on Pointers.  
  
 
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| We will do this with the help of an example
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| We will do this with the help of an example.
  
 
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|To record this tutorial I am using Ubuntu operating system version 11.10
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|To record this tutorial I am using '''Ubuntu operating system''' version 11.10,
  
 
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| gcc and g++ compiler version 4.6.1 on Ubuntu
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| '''gcc and g++ compiler''' version 4.6.1 on Ubuntu.
  
 
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|Let us start with an introduction to pointers
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|Let us start with an introduction to pointers.
  
 
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|Now, let us see an example on pointers
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|Now, let us see an example on pointers.
  
 
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|Note that our file name is '''pointers_demo.c'''
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|Note that our file name is '''pointers_demo.c'''.
  
 
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|Let us go through the code now
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|Let us go through the code now.
  
 
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|This is our header file as '''stdio.h'''
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|This is our header file as '''stdio.h'''.
  
 
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|This is our main function
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|This is our main() function.
  
 
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|Here we have '''long integer num''' assigned value '''10.'''
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|Here we have '''long integer num''', assigned value '''10.'''
  
 
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|Then we have declared a pointer ptr.  
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|Then we have declared a pointer '''ptr'''.  
  
 
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|In the printf statement ampersand is used for retrieving memory address of the variable.  
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|In the printf() statement, ampersand is used for retrieving memory address of the variable.  
  
 
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|So ampersand num will give the memory address of num.  
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|So, ampersand num (&num) will give the memory address of '''num'''.  
  
 
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|Over here ptr stores the address of num.  
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|Over here, ptr stores the address of num.  
  
 
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|Sizeof function will give the size of ptr.  
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|Size of function will give the size of ptr.  
  
 
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Revision as of 13:20, 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