Introduction to Pointers in C language

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Hello everyone!!


Today we are going to discuss Pointers in C language.

This article will include the following points:-

1) Definition
2) Syntax
3) Diagrammatic Representation
4) Initialization and Declaration
5) Dereference/indirection operator
6) Advantages and
7) Applications of pointers.

Let’s start quickly 🙂

What are Pointers:- A pointer is a variable which stores the address of another variable.

Syntax of declaring pointer is:-

data type *pointervariable; 

For Example:- int *p; It declares pointer p pointing to integer variable.

Note:- Pointer also has its own address.

Diagrammatic Representation of Pointer:-

In the diagram below i is a variable having value 5 and address 65524.

j is a pointer variable which holds the address of variable i. i.e 65524 and also j is having its own address in memory.

C language - representation of Pointers
Representation of Pointer

Initialization of C Pointer variable:-

  • Pointer Initialization is the process of assigning address of a variable to a pointer variable.
  • It contains the address of a variable of the same data type.
  • In C language address operator & is used to determine the address of a variable. The & (immediately preceding a variable name) returns the address of the variable associated with it.

Pointer Declaration and Initialization:-

int a = 10;
int *ptr; //pointer declaration
ptr = &a; //pointer initialization .

Pointer variable always points to variables of the same datatype.

Pointer Initialization and Declaration

Dereference/Indirection Operator:-

  • The dereference operator is also known as an indirection operator, which is represented by (*).
  • When indirection operator (*) is used with the pointer variable, then it is known as dereferencing a pointer.
  • When we dereference a pointer, then the value of the variable pointed by this pointer will be returned.

Examples of Dereferencing:-

Q1) C program used to change the value stored at pointer variable.

#include<stdio.h>  

int main()  
{  
 int x=9;  
 int *ptr; //Declaration of pointer variable
 
 ptr=&x; // Address of variable x is stored in ptr pointer variable 
 *ptr=8; //This statement is used to change the value stored at pointer variable  
 printf("value of x is : %d", x);  
}  

Output:- 8

Q2) C program to access the value using the pointer.

#include<stdio.h> 
int main ( )  
{ 
 int a = 20; 
 int *p;  
 p = &a; 
 printf("Address of variable: %u\n", &a );  
 printf("Address stored in variable: %u\n", p );  
 printf("Value of variable: %d\n", *p ); 
} 

Output:-
Address of variable: 1464212924
Address stored in variable: 1464212924
Value of variable: 2

Advantage of pointer:-

  • Pointer reduces the code and improves the performance, it is used to retrieving strings etc. and used with arrays, structures, and functions.
  • We can return multiple values from a function using the pointer.
  • It makes you able to access any memory location in the computer’s memory.

Applications of pointer:- There are many applications of pointers in C language.

  • Dynamic memory allocation.
    • In C language, we can dynamically allocate memory using malloc() and calloc() functions where the pointer is used.
  • Arrays, Functions, and Structures.
    • Pointers in C language are widely used in arrays, functions, and structures. It reduces the code and improves the performance.

Soo this is a short introduction of Pointers in C language. We will discuss Pointers in detail in upcoming articles.

Keep reading keep learning.


Thank you for reading 🙂 Have a wonderful day ahead 🙂

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