#include <stdio.h>

void foo(int * address) {
 
   int n;
   
   n = * address;
   printf("%d\n",n);
 
   * address = 31;

  return; 
}



int main() {

 int a;
 int * address; /* address is an address of an int value */

 a = 10;

 address = &a;
 foo(address);
 printf("%d\n",a); 

 
 return 0;
}