c/c++宏定义，#，## 代码实例

# —— 字符串

##——连接两个参数

#include <iostream>
using namespace std;

#define test(pid) (cout<<para##pid<<endl);
#define test2(p) (cout<<#p<<endl);
int main()
{
    int para3 = 3;
    int para2 = 2;
    test(2);    //<==>cout<<para2<<endl;
    test(3);    //<==>cout<<para3<<endl;

    test2(test)        //<==>cout<<"test"<<endl;
    test2("test2");    //<==>cout<<""test2""<<endl;
    system("pause");
    return 0;
}