knr/4.14.c

#undef swap
#define swap(t,w,y) { t temp=w; w=y; y=temp; }

#include <stdio.h>
int main()
{
  int x=1;
  int y=2;
  swap (int,x,y);
  printf("%d %d \n",x,y);
  return 0;
}