#include <iostream>

#define PI 3.14159265

using namespace std;

struct Coord {
    float x;
    float y;
    Coord() : x(0), y(0) {}
};

class Shape {
protected:
    Coord center;

public:
    /*Shape(){}*/
    virtual float area() = 0;        // 面積  抽象類別
    virtual float perimeter() = 0;   // 周長

    void Set(float x, float y)
    {
        center.x = x;
        center.y = y;
    }

    Coord GetCenter()
    {
        return center;
    }

    const Coord & GetCenterRef()
    {
        return center;
    }
};

class Reactangle : public Shape {
public:
    float width;
    float height;

public:
    Reactangle(float w, float h) : /*Shape(),*/ width(w), height(h)     // 不寫 Shape() 會自動呼叫父類別的 constructor
    {
    }

    virtual float area()
    {
        return width * height;
    }

    virtual float perimeter()
    {
        return width + width + height + height;
    }

};

class Square : public Reactangle {
public:
    Square(float w) : Reactangle(w, w)
    {
    }
};

class Circle : public Shape {
public:
    float radius;   // 半徑

public:
    Circle(float r) : radius(r)
    {
    }

    float area()
    {
        return radius * radius * PI;
    }

    float perimeter()
    {
        return (radius + radius) * PI;
    }

};

class Ellipse : public Shape {
private:
    float height;
    float width;

public:
    Ellipse(float h, float w) : height(h), width(w)
    {
    }

    float area() {
        return (height/2) * (width/2) * PI;
    }

    float perimeter() {
        float res;
        res = (width > height) ? 2*PI*(height/2) + 4*(width-height) : 2*PI*(width/2) + 4*(height-width);
        return res;
    }
};

ostream& operator << (ostream & out, Coord c)
{
    out << "(" << c.x << "," << c.y << ")";
    return out;
}