Question

c++填空，定义一个Shape抽象类，由它派生出Rectanglr和Circle类。。。。。非常感谢

定义一个Shape抽象类，由它派生出Rectanglr和Circle类，二者都有GetArea( )函数计算对象的面积，GetPerim( ) 函数计算对象的周长
#include <iostream.h>
class Shape
{
[①定义GetArea 和GetPerim函数 ______]
};
class Circle:public Shape
{
public:
Circle(float radius):itsRadius(radius){}
float GetArea(){return 3.14*itsRadius*itsRadius;}
float GetPerim(){return 6.28*itsRadius;}
private:
float itsRadius;
};
class Rectangle : public Shape
{
public:
[②定义Rectangle构造函数_____________]
[③定义 GetArea()和 GetPerim()函数_______]
private:
float GetLength(){return itsLength;}
float GetWidth(){return itsWidth;}
private:
float itsWidth;
float itsLength;

Answer 1

1. virtual float GetArea() = 0;
virtual float GetPerim() = 0; //两个纯虚函数
2. Rectangle(float width, float length):itsWidth(width), itsLength(length){}
3. float GetArea() {return itsWidth* itsLength;}
float GetPerim() {return 2 * (itsWidth + itsLength);}

Answer 2

1. virtual float GetArea() = 0;
virtual float GetPerim() = 0;

2. Rectangle(float width, float length):itsWidth(width), itsLength(length){}

3. float GetArea() {return itsWidth* itsLength;}
float GetPerim() {return 2 * (itsWidth + itsLength);}