一段好玩的代码

 

这是编程之美上的一段代码，使用一个字节的空间，计算象棋中将帅的位置关系

这里是书中最简单的一个代码段：

//#include <stdio.h>
#include <iostream>

#define HALF_BITS_LENGTH 4
#define FULLMASK 255
#define LMASK (FULLMASK << HALF_BITS_LENGTH)//1111000
#define RMASK (FULLMASK >> HALF_BITS_LENGTH)//00001111
#define RSET(b,n) (b = ((LMASK & b) ^ n))
#define LSET(b,n) (b = ((RMASK & b) ^ (n << HALF_BITS_LENGTH)))
#define RGET(b) (RMASK & b)
#define LGET(b) ((LMASK & b) >> HALF_BITS_LENGTH)
#define GRIDW 3

int main()
{
 unsigned char b = 0;
 for(LSET(b,1); LGET(b) <= GRIDW * GRIDW;LSET(b,(LGET(b)+1)))
 {
  for(RSET(b,1); RGET(b) <= GRIDW * GRIDW;RSET(b,(RGET(b)+1)))
  {
   if(LGET(b)%GRIDW != RGET(b)%GRIDW)
   {
    std::cout<<"A = "<<LGET(b)<<"B= "<<RGET(b)<<std::endl;
    //printf("A=%d,B = %d\n",LGET(b),RGET(b));
   }
  }
 }
 return 0;
}