二位几何运算类

#include <cstdio>
#include <cstring>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <cmath>

using namespace std;
struct Point
{
    int x,y;
    Point(int x = 0,int y = 0): x(x),y(y) {}
    Point operator = (Point p) {x = p.x;y = p.y;return *this;}
};

Point operator + (const Point& A,const Point& B){return Point(A.x+B.x,A.y+B.y);}
Point operator - (const Point& A,const Point& B){return Point(A.x-B.x,A.y-B.y);}
Point operator * (const Point& A,int p){return Point(A.x*p,A.y*p);}
bool operator == (const Point& A,const Point &B) {return A.x==B.x && A.y == B.y;}
bool operator < (const Point& p1,const Point& p2) {return p1.x < p2.x || (p1.x==p2.x && p1.y < p2.y);}
istream & operator >> (istream& is,Point& p) {return is >> p.x >> p.y;}
ostream & operator << (ostream& os,Point& p) {return os << p.x << " " << p.y;}
int main()
{
    Point p1(3,4),p2(7,8);
    if(p1<p2)
        cout << "p1 is smaller than p2" << endl;
    Point p3 = p1 + p2;
    cout << p3 << endl;
    Point p4;
    cin >> p4;
    cout << p4 << endl;
    p4 = p3*3;
    cout << p4 << endl;
    return 0;
}