[编程之美]中国象棋将帅问题

熟悉位操作符和位的存储方法

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 1 #include <stdio.h>
 2 
 3 #define LMASK (255 << 4)
 4 #define RMASK (255 >> 4)
 5 #define LGET(d) ((d&LMASK) >> 4)
 6 #define RGET(d) (d&RMASK)
 7 #define LSET(d,n) (d=((d&RMASK) | (n << 4)))
 8 #define RSET(d,n) (d=((d&LMASK) | n))
 9 
10 int main()
11 {
12     unsigned char b=0;
13     for(LSET(b,1);LGET(b)<=9;LSET(b,(LGET(b)+1)))
14         for(RSET(b,1);RGET(b)<=9;RSET(b,(RGET(b)+1)))
15             if(LGET(b)%3!=RGET(b)%3)
16                 printf("A=%d,B=%d\n",LGET(b),RGET(b));
17     return 0;
18 }

 

还有一种更为简单明了的方法

View Code

 1 struct 
 2 {
 3     unsigned char a:4;
 4     unsigned char b:4;
 5 }chess;
 6 
 7 int main()
 8 {
 9     for(chess.a=1;chess.a<=9;++chess.a)
10         for(chess.b=1;chess.b<=9;++chess.b)
11             if(chess.a%3!=chess.b%3)
12                 printf("A=%d,B=%d\n",chess.a,chess.b);
13     return 0;
14 }