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（

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#include
using namespace std;
#define PI 3.14
class Point
{public:
\x09Point() :m_x(0),m_y(0){}
\x09Point(double x,double y) :m_x(x),m_y(y){}
\x09~Point(){}
protected:
\x09double m_x;
\x09double m_y;
};class Rectangle :public Point
{public:
\x09Rectangle() :Point(){}
\x09Rectangle(double x,double y) :Point(x,y){}
\x09~Rectangle(){}
\x09double Area()
\x09{\x09\x09return m_x * m_y;
\x09}};class Circle :public Point
{public:
\x09Circle() :m_r(0){}
\x09Circle(double r) :m_r(r){}
\x09~Circle(){}
\x09double Area()
\x09{\x09\x09return PI * m_r * m_r;
\x09}private:
\x09double m_r;
};int main()
{\x09Rectangle rect(3.2,2.1);
\x09Circle circle(5.1);
\x09cout