#include <stdio.h>

void next(int *ptr)
   /* effect: increment *ptr by 4 */
{
   *ptr += 4;
}

int main()
{
  extern void next(int *ptr);
  int i = 3;
  int *ptr = &i;
  next(&i);
  next(ptr);
  printf("%d %d\n", i, *ptr);
  return 0;
}