C ++条件运算符在全局函数中使用时无法正常工作

Question

I am trying to use conditional operators to do the simple max/min functions that compare the values between two integers, but I found out that when I use those conditional operators globally in functions, they do not work as expected, but they do work well when I put the exact same codes locally.

In the code below, I've tried 4 methods (as indicated by the comments below), and method 2, 3, as well as 4 all work well, yet method 1 (which uses the same conditional operators as in method 4, but globally) just does not yield the correct results.

//For method 1 to method 4, pick one and comment out the others.

#include <iostream>

//Method 1: Does not work, yields "1,1".
int max(int a, int b){(a) > (b) ? (a) : (b);}
int min(int a, int b){(a) < (b) ? (a) : (b);}

//Method 2: Works well, yields "2,1".
#define max(x, y) ((x) > (y) ? (x) : (y))
#define min(x, y) ((x) < (y) ? (x) : (y))

//Method 3: Works well, yields "2,1".
int max(int a, int b){if(a > b) return a; else return b;}
int min(int a, int b){if(a < b) return a; else return b;}

int main(void)
{
    int a = 1, b = 2;

//Method 4: Works well, yields "2,1".
int large = ((a) > (b) ? (a) : (b));
int small = ((a) < (b) ? (a) : (b));

    int large = max(a,b); //Comment out when using Method 4.
    int small = min(a,b); //Comment out when using Method 4.

    std::cout << large << "," << small << std::endl;

    return 0;
}

Answer 1

int max(int a, int b){(a) > (b) ? (a) : (b);}

You forgot a "return" statement in there. It is required to indicate the value returned from a function.

Your compiler should've warned you about this. Especially when learning C++, it is useful to turn on all compiler diagnostics that you can think of. Every compiler worth it's salt would've complained about code like this.