Example 3: An example to illustrate partial transfer functions

main( )
{
      int *a, *b, c, d;
      a = &c; b = &d;

      for(i=0; i<2; i++) {
      foo(&a, &a);
      foo(&b, &b);
      foo(&a, &b);
      foo(&b, &a);
      }
}

foo( int** x, int** y)
{
      int *temp = *x;
      *x = *y;
      *y = temp;	
}