MOOC清华《面向对象程序设计》第3章：const常量成员实验

#include <iostream>using namespace std;class Test{const int ID;public:Test(int id): ID(id) {}int MyID() const {return ID;}//int Next() const {ID++; return ID;} //报错：increment of member 'Test::ID' in read-only object int Who() {return ID;}};int main(){Test obj_1(20050903);cout << "ID_1 = " << obj_1.MyID() << endl;cout << "ID_2 = " << obj_1.Who() << endl;const Test obj_2(20090630);cout << "id_1 : " << obj_2.MyID() << endl;//cout << "id_2 : " << obj_2.Who() << endl; //报错：passing 'const Test' as 'this' argument of 'int Test::Who()' discards qualifiers [-fpermissive] return 0;}