/*C program to change the value of constant integer using pointers.*/

#include <stdio.h>

int main()
{   
    const int a=10;     //declare and assign constant integer
    int *p;             //declare integer pointer
    p=&a;               //assign address into pointer p
     
    printf("Before changing - value of a: %d",a);
     
    //assign value using pointer
    *p=20;
     
    printf("\nAfter  changing - value of a: %d",a); 
    printf("\nWauuuu... value has changed.");
     
    return 0;
}

Output

    Before changing - value of a: 10
    After  changing - value of a: 20
    Wauuuu... value has changed.