C #与##的使用

#include <iostream>
using namespace std;

#define STR(s) #s  // #的用法，转化为字符串
#define CONCAT(s1, s2) s1##s2  // ##连接后，作为变量名

#define MAX(a, b)\
                {if((a)>(b))\
                    return (a);\
                else\
                    return (b);\
                }
                
#define swap(x, y)\
x = x + y;\
y = x - y;\
x = x - y;

#define Swap(x, y)\
    int t = x;\
    x = y;\
    y = t;
    
#define max(a, b) (if (a < b) a; else b;)

int main()
{
    cout << STR(test) << endl;
    int ab = 10;
    cout << CONCAT(a, b) << endl;
    cout << STR(CONCAT(a, b)) << endl;
    
    // cout << MAX(10, 3) << endl;
    int a = 10, b = 11;
    Swap(a, b);
    cout << max(a, b) << endl;
    return 0;
}