#include <stdio.h>
#include <stdlib.h>

int main (int argc, char** argv){
   int *x1;
   int x2;
   int *x3;

   x1 = (int*) malloc (sizeof(int));
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);

   *x1 = 20;
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);

   x2 = *x1;      
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);

   *x3 = x2 * *x1;
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);

   x3 = &x2;
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);

   x2 = 15;
   printf("\nx1(%p)(%i)(%p) x2(%i)(%p) x3(%p)(%i)(%p)", x1, *x1, &x1, x2, &x2, x3, *x3, &x3);
   printf("\n");
}