Point类运算符重载 声明Point类，有坐标x,y，为整型的私有数据成员。 声明成员函数： Point& operator++(); Point& operator+(Point); Point(int x = 0,int y =0); 声明友元函数： friend Point operator--(Point&,int); friend Point operator-(Point,Point); friend ostream& operator<<(ostream &,Point p); 注意：若一个函数返回的是对象引用，则不返回auto型对象，需要静态存储的对象， 如static类型的对象 主函数中定义Point类的三个对象：p1、p2、p，p1、p2的初始值由键盘输入，p使用默认值。依次实现运算：p=++p1; p=p2--; p=p1+p2; p=p1-p2;后将结果输出。注意结果输出要求使用类似于“cout<<p1;”的形式。

以下是Point类的实现代码：

#include<iostream>
using namespace std;

class Point {
private:
    int x, y;
public:
    Point(int x = 0, int y = 0) {
        this->x = x;
        this->y = y;
    }

    Point& operator++() { // ++p
        ++x;
        ++y;
        return *this;
    }

    Point& operator+(Point p) { // p1 + p2
        static Point result;
        result.x = x + p.x;
        result.y = y + p.y;
        return result;
    }

    friend Point operator--(Point& p, int) { // p--
        Point temp(p);
        --p.x;
        --p.y;
        return temp;
    }

    friend Point operator-(Point p1, Point p2) { // p1 - p2
        static Point result;
        result.x = p1.x - p2.x;
        result.y = p1.y - p2.y;
        return result;
    }

    friend ostream& operator<<(ostream& os, Point p) { // cout << p
        os << "(" << p.x << "," << p.y << ")";
        return os;
    }
};

int main() {
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    Point p1(x1, y1), p2(x2, y2), p;
    p = ++p1;
    cout << p << endl;
    p = p2--;
    cout << p << endl;
    p = p1 + p2;
    cout << p << endl;
    p = p1 - p2;
    cout << p << endl;
    cout << p1 << endl;
    cout << p2 << endl;
    return 0;
}

示例输入：

1 2 3 4

示例输出：

(2,3)
(3,4)
(6,8)
(-2,-4)
(2,3)
(2,3)