# include <stdio.h>

//
//  Program 11.9, Stephen Kochan, Programming in C.
//
int main ( void );
void exchange ( int *const pint1, int *const pint2 );

int main ( void )
{
  int i1 = -5, i2 = 66, *p1 = &i1, *p2 = &i2;

  printf ( "i1 = %i, i2 = %i\n", i1, i2 );

  exchange ( p1, p2 );
  printf ( "i1 = %i, i2 = %i\n", i1, i2 );

  exchange ( &i1, &i2 );
  printf ( "i1 = %i, i2 = %i\n", i1, i2 );

  return 0;
}

void exchange ( int *const pint1, int *const pint2 )
{
  int temp;

  temp = *pint1;
  *pint1 = *pint2;
  *pint2 = temp;

  return;
}