#define A  2
#define paste(a)  #a
#define ps(a,b)  a##b

int main(){
   
    printf("test1: %s \n",paste(ps(ps(ps(A,B),C),D)));  
    printf("test2: %s \n",paste(ps(ps(ps(\A,B),C),D)));

    printf("test3: %s \n",paste(ps(ps(p\s(\A,B),C),D)));
    printf("test4: %s \n",paste(ps(ps(p\\s(\A,B),C),D)));

    printf("test5: %s \n",paste(ps(p\s(p\s(A,B),C),D)));
    printf("test6: %s \n",paste(ps(p\s(p\s(\A,B),C),D)));

    printf("test7: %s \n",paste(ps(p\\s(ps(\A,B),C),D)));
    return 0;
}

输出结果如下：
test1: 2BCD
test2: ABCD

test3: ps(2 ,B)CD
test4: ps(A,B)CD

test5: ps(ps(2 ,B),C)
test6: ps(ps(2 ,B),C)

test7: ps(AB ,C)D

哪位大神帮忙分析下为什么转义符号在不同的地方，出现了不同的结果！！！

你用的是VC6吧，换个编译器吧

我用的turbo c!

int main(){
    printf("test1: %s \n","ps(ps(ps(A,B),C),D)");
    printf("test2: %s \n","ps(ps(ps(\A,B),C),D)");

    printf("test3: %s \n","ps(ps(p\s(\A,B),C),D)");
    printf("test4: %s \n","ps(ps(p\\s(\A,B),C),D)");

    printf("test5: %s \n","ps(p\s(p\s(A,B),C),D)");
    printf("test6: %s \n","ps(p\s(p\s(\A,B),C),D)");

    printf("test7: %s \n","ps(p\\s(ps(\A,B),C),D)");
    return 0;
}

上面是gcc4.9.2的预处理的结果。对于预处理中的#说明见
http://bbs.
https://msdn.

没看到结果！~