C++自定义对象作map键及比较实现

class Point {
public:
    int x, y;
    Point(int x, int y) : x(x), y(y) {}

    // 重载 < 操作符
    bool operator<(const Point& other) const {
        if (x != other.x)
            return x < other.x;
        return y < other.y;
    }
};

std::map<Point, std::string> pointMap;
pointMap[Point(1, 2)] = "origin";
pointMap[Point(3, 4)] = "far point";

struct ComparePoint {
    bool operator()(const Point& a, const Point& b) const {
        if (a.x != b.x)
            return a.x < b.x;
        return a.y < b.y;
    }
};

std::map<Point, std::string, ComparePoint> pointMap;

#include <iostream>
#include <map>
#include <string>

class Point {
public:
    int x, y;
    Point(int x, int y) : x(x), y(y) {}
    
    bool operator<(const Point& other) const {
        if (x != other.x) return x < other.x;
        return y < other.y;
    }
};

int main() {
    std::map<Point, std::string> m;
    m[Point(1, 2)] = "first";
    m[Point(1, 3)] = "second";

    for (const auto& pair : m) {
        std::cout << "(" << pair.first.x << "," << pair.first.y 
                  << "): " << pair.second << "\n";
    }
    return 0;
}