10/24 C++: Point2D

#include <iostream>
using namespace std;

class Point2D{
    private:
        // 資料 (變數部分)
        double x;
        double y;

    public:

        friend void OutputPoint2D(Point2D v);

        // 操作 (函式部分)
        Point2D(){
            x = 0;
            y = 0;
        }

        Point2D(double a, double b){
            x = a;
            y = b;
        }

        double getX(){
            return x;
        }

        double getY(){
            return y;
        }

        Point2D operator*(Point2D b){
            double i = x * b.x;
            double j = y * b.y;
            Point2D c( i, j );
            return c;
        }

};

void OutputPoint2D(Point2D v){
    cout << "(" << v.x << "," << v.y << ")" << endl;
}



int main(){
    int x, y;

    cin >> x >> y;
    Point2D p1(x, y);
    cin >> x >> y;
    Point2D p2(x, y);

    Point2D p3;
    p3 = p1 * p2;
    OutputPoint2D( p3 );
    return 0;
}