这个怎么写呀，挺急的

结合main函数的代码，编写一个Point类，需要满足如下要求：1)数据成员包含：横坐标，纵坐标2)定义构造函数和析构函数3)重载+（加法）、-（减法）运算符 (提示:相应坐标值的加减)4)重载=（赋值）运算符5)重载> （提取运算符)int main(){       Point p1,p2,p3(3,4);    cin>>p2;    p1=p2+p3;    cout<<p1;    p1=p2-p3;    cout<<p1;    return 0;}

#include <iostream>
using namespace std;

class Point
{
private:
    int x,y;

public:
    Point(int x,int y);
    Point();
    ~Point();

    Point operator+(const Point &a);
    Point operator-(const Point &a);
    Point& operator=(const Point &a);

    friend ostream &operator<<(ostream &os, const Point &a);
    friend istream &operator>>(istream &in, Point &a);
};

Point::Point(int x,int y)
{
    this->x=x;
    this->y=y;
}

Point::Point()
{
    Point(0,0);
}

Point::~Point()
{
}

Point Point::operator+(const Point &a)
{
    Point tmp;
    tmp.x=this->x + a.x ;
    tmp.y=this->y + a.y ;

    return tmp;
}

Point Point::operator-(const Point &a)
{
    Point tmp;
    tmp.x=this->x - a.x ;
    tmp.y=this->y - a.y ;

    return tmp;
}

Point& Point::operator=(const Point &a)
{
    this->x=a.x;
    this->y=a.y;
    return *this;
}

ostream& operator<<(ostream &os, const Point &a)
{
    os << "x=" << a.x << " y=" << a.y << endl ;
    return os;
}

istream& operator>>(istream &in, Point &a)
{
    in >> a.x >> a.y;
    return in;
}


int main()
{
    Point p1, p2, p3(3, 4);
    cin >> p2;
    p1 = p2 + p3;
    cout << p1;
    p1 = p2 - p3;
    cout << p1;

    return 0;
}

直接写 class Point{private: int x,int y};