类成员的运算符重载函数例

/*

我写他的目的是以防以后忘记这些基础的东西，每隔一段时间就过一遍程序，这比看书有效率

*/

#include <iostream>
using namespace std;
class point
{
      private:
              int x;
              public:
                     point():x(1){}
                     point(int);
                     // must take either zero or one argument
                     /*int operator +(point &obj2,point &obj3)
                     {
                     int a;
                     a=this->x+obj2.x+obj3.x;
                     return a; 
                     }*/
      int operator+(point obj2)
      {
       int a;
       a=this->x+obj2.x;
     
       return a;
      
          
      }
      int operator !()
       {
        if(x==0)return 0;
        else
        return 1;   
       }
      };
      point::point(int a)
      {
       x=a;
                  
      }
     
      int main()
      {
          point obj_1(0);
          point obj_2(1);
          point obj_3(2);
          cout<<!obj_1<<endl;
          cout<<!obj_2<<endl;
          cout<<!obj_3<<endl;
          cout<<obj_1+obj_2<<endl;
          cout<<obj_2+obj_3<<endl;
          system("pause");
          return 0;
          }
结果为:0,1,1,1,3