Class 9 | Pointer | C Programming Notes

Pointer

 

A pointer is a special variable that stores the memory address of another variable. A pointer also needs to be declared in a program but cannot store data instead it stores the memory address of a variable.

 

Eg:

 

Let us declare an integer variable:

 

Int a;

 

Then the corresponding pointer variable which can point to a memory address of integer variable should be of

 

integer type.

 

i.e. int*p;

 

here, ‘p’ is a pointer variable that can store the address of ‘a’ but it cannot store the address of another type variable. For example, P cannot store the address of the float variable.

 

Address operator(&):

 

The unary operator which returns the address of a variable, is known as address operator.

 

Declaring pointer and pointer variable

 

The syntax of declaring a pointer variable is:

 

Data_type*variable_name;

 

Eg:

 

Int*p;

 

Here, ‘p’ is an integer pointer which holds the memory address of an integer variable.

 

Char*c;

 

Here, ‘c’ is a character pointer which holds the memory address of a character variable.

 

Float*d;

 

Here, ‘d’ is a float pointer which holds the memory address of a float variable.

 

REFERNCING AND DEREFERENCING

 

Referencing of a pointer refers to the process of making a pointer variable point to another variable by providing an address of that variable to the pointer variable.

 

Pointer initialization

 

Syntax:

 

Pointer variable = &normal_variable;

 

Eg:

 

Int a=57;

 

Int*p;

 

P=&a;

 

DERDFERENCING OF A POINTER

 

It is a process where ‘*’ is used with the pointer variable to return the value of the normal variable pointed by the pointer variable.

 

Syntax:

 

*pointer_variable;

 

Eg:

 

#include<stdio.h>

 

Void main()

 

Int*p, a=20;

 

P=&a;

 

Printf(“the address of a is: %d”, &a);

 

Printf(“\n the value of p is: %d”, p);

 

Printf(“\n the value of a is: %d”, a);

 

Printf(“\n the value of *p is: &d”, *p);

 

}

 

ADVANTAGE OF POINTER

 

The advantage of pointers are listed below:

 

• Pointer make program simple and also saves memory space.

 

• It enhance the execution speed of a program as they refer to the address.

 

• Pointers are useful for accessing memory locations.

 

• It is used for dynamic memory allocation and deallocation during the execution of a program.

 

• Pointer is closed to the array so it is efficient for solving array and string related problems.