What is Pointer in C Language with Free Notes

Pointer

Pointer is a variable which stores the address of another variable. Since Pointer is also a kind of variable, thus pointer itself will be stored at different memory location.

Example:

#include<stdio.h>
void main()
{ 
   int a = 10:
   int *ptr;
   ptr = &a;
}

Example can be Explained as:

Point	Variable ‘a’	Variable ‘ptr’
Name of variable	a	ptr
Type of value that it holds	Integer	Address of Integer ‘a’
Value Stored	10	2002
Address of Variable	2002 9Assumption)	4004 (Assumption

Example:

#include<stdio.h>
void main()
{  
   int a = 3;
   int *ptr, **ptr;
   ptr = &a;
   pptr = &ptr;
}

It can be explained as,

Point	Variable ‘a’	Variable ‘ptr’	Variable ‘pptr’
Name of Variable	A	ptr	pptr
Type of value that it holds	Integer	Address of ‘a’	Address of ‘ptr’
Value Stored	10	2002	4004
Address of variable	2002	4004	6006

The above table can be explained as:

1. a is the name given for particular memory location of ordinary variable.
2. Let us consider it’s Corresponding address be 2002 and the value stored in variable ‘a’ is 10.
3. The address of the variable ‘a’ is stored in another integer variable whose name is ‘ptr’ and which is having corresponding address 4004.
4. The address of the variable ‘ptr’ is stored in another integer variable whose name is ‘pptr’ and which is having corresponding address 6006.

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Example:

#include<stdio.h>
void main()
{
   int *ptr, i;
   i = 10;

    //Address of i assigned to the ptr
     ptr = &i;
     
    //Show the value of i using ptr variable
    printf("value of i = %d", *ptr);
   }

Key Points of Pointer

1. Unlike ordinary variables pointer is special type of variable which stores the address of ordinary variable.
2. Pointer can only store integer number because address of any type of variable is considered as integer.
3. It is always better to initialize the pointer immediately after declaration.
4. & symbol is used to get address of a variable.
5. symbol is used to get value from the address given by pointer.

Advantages of Using Pointer

There are many reasons for using pointers, some of these are: –

1. Sometimes it is more convenient or flexible to work with the address of a variable than the actual variable.
2. With the use of pointer program execution becomes fater.
3. Pointers are used for storing address of a dynamically allocated block of memory.
4. Using a pointer, your program can access any memory location in the computer’s memory.
5. Pointers allow a function to pass back more than one value by writing then into memory locations that are accessible to the calling function.
6. Using pointers, arrays and structures can be handled in more efficient way.
7. Low level system programming can be done through the use of pointers.
8. It will become impossible to create complex data structures without pointers. These are link list, tree, graphs, etc.