01  #include<stdio.h>
02  
03  int main()
04  {
05  int x=50; //integer variable
06  
07  int *ptr; //integer pointer
08  
09  printf("Value of X : %d n",x);
10  
11  ptr= &x; // ptr points to 'x'
12  
13  *ptr=100; // x=100
14  
15  printf("Value of X : %d n",x);
16  
17  return 0;
18  }

 OUTPUT :
 
 Value of X : 50
 Value of X : 100