c++运算符重载

作为成员函数重载

     class Point {
     public:
         int x;
         int y;
         Point(int a = 0, int b = 0) : x(a), y(b) {}
         bool operator<(const Point& other) const {
             if (x!= other.x) {
                 return x < other.x;
             } else {
                 return y < other.y;
             }
         }
         bool operator>(const Point& other) const {
             return other < *this;
         }
     };

作为全局函数重载（结合友元函数）

     class Point {
     public:
         int x;
         int y;
         Point(int a = 0, int b = 0) : x(a), y(b) {}
         friend bool operator<(const Point& p1, const Point& p2);
         friend bool operator>(const Point& p1, const Point& p2);
     };
     bool operator<(const Point& p1, const Point& p2) {
         if (p1.x!= p2.x) {
             return p1.x < p2.x;
         } else {
             return p1.y < p2.y;
         }
     }
     bool operator>(const Point& p1, const Point& p2) {
         return p2 < p1;
     }

在容器中使用重载的<和>运算符（以set容器为例）

     #include <iostream>
     #include <set>
     int main() {
         std::set<Point> s;
         s.insert(Point(1, 2));
         s.insert(Point(3, 4));
         s.insert(Point(1, 3));
         for (const auto& p : s) {
             std::cout << "(" << p.x << ", " << p.y << ")" << std::endl;
         }
         return 0;
     }