第3关:计算图像面积
#includeusing namespace std; class Shape { public: virtual void PrintArea()=0;//基类的声明 }; class Rectangle : public Shape { public: float width; float height; void PrintArea() { cout<<"矩形面积 = "<

第3关:计算图像面积
#includeusing namespace std; class Shape { public: virtual void PrintArea()=0;//基类的声明 }; class Rectangle : public Shape { public: float width; float height; void PrintArea() { cout<<"矩形面积 = "<