Pointer

A pointer is a variable that store the address of another variable direct address of the memory location. Thus, the variable can be type of int, char , array, function or any other pointer. Variable or constant you must declare a pointer before using it to store any variable address.However, in 32-bit architecture the size of a pointer is 2 byte.

The following example to define a pointer which stores the address of an integer

int n=20;
int*p = &n;

Declaring a pointer

In C language pointer can be declared using * (asterisk symbol).

int*a;
char *c;

Let’s see the example of pointer

#include <stdio.h> 
int main() 
{ 
     
    int Var = 10;  
    int *ptr = &Var;
    printf("Value of Var = %d\n", *ptr); 
    printf("Address of Var = %p\n", ptr); 
    *ptr = 20;  
    printf("After doing *ptr = 20, *ptr is %d\n", *ptr); 
  
    return 0; 
}

Output

Value of Var = 10
Address of Var = 0x7fffa057dd4
After doing *ptr = 20, *ptr is 20

Pointer to array

int arr[10];
int *p[10]=&arr;

Pointer to function

void show(int);
void(*p)(int)=&display;

Pointer to structure

struct st{
int i;
float f;
}ref;
struct st*p = &ref;

Address Of “&” operator

#include<stdio.h>  
int main(){  
int number=50;   
printf("value of number is %d, address of number is %u",number,&number);    
return 0;  
}

Output

value of numberis 50, address of number is fff4.

Reading complex pointers

let’s see the precedence and associativity of the operators which are used regarding pointers.