请创建一个抽象类Shape，在此基础上继承出Rectangle和Circle类，并让这三者都具备计算对象面积和周长的函数getAreaC和getPerimC

#include

#include

using namespace std;

class Shape

{

public:

Shape(){}

~Shape(){}

public:

virtual double getArea() const = 0;

virtual double getPerim() const = 0;

private:

};

class Rectangle : public Shape

{

public:

Rectangle(double _length, double _width) : length(_length), width(_width){}

~Rectangle(){}

public:

double getArea() const {return length * width;}

double getPerim() const {return 2 * (length + width);}

private:

double length;

double width;

};

class Circle : public Shape

{

public:

Circle(double _radius) : radius(_radius){}

~Circle(){}