C++ 判断一个多边形是否为矩形

以下是判断一个多边形是否为矩形的C++代码：

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

struct Point {
    int x, y;
    Point(int x = 0, int y = 0) :x(x), y(y) {}
};

typedef Point Vector;

Vector operator-(Point A, Point B) {
    return Vector(A.x - B.x, A.y - B.y);
}

int Cross(Vector A, Vector B) {
    return A.x * B.y - A.y * B.x;
}

int Area2(Point A, Point B, Point C) {
    return Cross(B - A, C - A);
}

bool IsRectangle(vector<Point>& p) {
    int n = p.size();
    if (n != 4) return false;
    for (int i = 0; i < n; i++) {
        if (Area2(p[i], p[(i + 1) % n], p[(i + 2) % n]) == 0) {
            Vector v1 = p[(i + 1) % n] - p[i];
            Vector v2 = p[(i + 2) % n] - p[(i + 1) % n];            if (v1.x * v2.x + v1.y * v2.y != 0) return false;
        }
    }
    return true;
}

int main() {
    vector<Point> p;
    p.push_back(Point(0, 0));
    p.push_back(Point(0, 1));
    p.push_back(Point(1, 1));
    p.push_back(Point(1, 0));
    if (IsRectangle(p)) {
        cout << "Yes" << endl;
    }
    else {
        cout << "No" << endl;
    }
    return 0;
}