Question

定义一个Point类，派生出Rectangle类和Circle类，计算各 派生类对象的面积Area（）。

急求，各位高手高高手，伸出手来来吧

Answer 1

#include <iostream>
using namespace std;

#define PI 3.14

class Point
{
public:
Point() : m_x(0), m_y(0){}
Point(double x, double y) : m_x(x), m_y(y){}
~Point(){}
protected:
double m_x;
double m_y;
};

class Rectangle : public Point
{
public:
Rectangle() : Point(){}
Rectangle(double x, double y) : Point(x, y){}
~Rectangle(){}
double Area()
{
return m_x * m_y;
}
};

class Circle : public Point
{
public:
Circle() : m_r(0){}
Circle(double r) : m_r(r){}
~Circle(){}
double Area()
{
return PI * m_r * m_r;
}
private:
double m_r;
};

int main()
{
Rectangle rect(3.2, 2.1);
Circle circle(5.1);
cout << "rect area : " << rect.Area() << endl;
cout << "circle area : " << circle.Area() << endl;
return 0;
}