#include <stdio.h>

/*  Permute les entiers pointés par p1 et p2.  */

static void permuter(int *p1, int *p2)
{
  int aux;

  aux = *p1;
  *p1 = *p2;
  *p2 = aux;
}

int main()
{
  int a, b;

  a = 42;
  b = -7;

  printf("a = %d, b = %d\n", a, b);
  permuter(&a, &b);
  printf("a = %d, b = %d\n", a, b);

  return 0;
}