main()                      /* illustration of pointer use */
{
int index,*pt1,*pt2;

   index = 39;                      /* any numerical value */
   pt1 = &index;                   /* the address of index */
   pt2 = pt1;
   printf("The value is %d %d %d\n",index,*pt1,*pt2);
   *pt1 = 13;           /* this changes the value of index */ 
   printf("The value is %d %d %d\n",index,*pt1,*pt2);
}