EffectiveC++ 条约2的疑问

EffectiveC++ 条款2的疑问
代码如下：

C/C++ code

#define CALL_WITH_MAX(a, b) ((a) > (b) ? (a) : (b))int main(){    int a = 5, b = 0;    CALL_WITH_MAX(++a, b);//这里为什么a会被累加两次？    std::cout << "a: " << a << ", b: " << b << std::endl;    CALL_WITH_MAX(++a, b+10);    std::cout << "a: " << a << ", b: " << b << std::endl;}