c++问题提问，圆柱体类

Question

应该需要用到对象的创建和撤销，用cylinder
创建圆柱体类，这个程序整体怎么写
下午要用

Answer 1

供参考

#include <iostream>
using namespace std;

const float PI = 3.1415926;

class Circle
{
    private :
        float radius;        
    public:
        Circle()
        {
            radius = 0;
        }
        Circle(float R)
        {
            radius = R;
        }
        float area()
        {
            return PI * radius * radius;
        }
        float line()
        {
            return PI * 2 * radius;
        }
};

class Cylinder:Circle
{
    private:
        float height;
    public:
        Cylinder();
        Cylinder(float r, float h);
        ~Cylinder();
        float area();

};

Cylinder::Cylinder(float r, float h):Circle(r)
{
    height=h;
    cout << height<< endl;
}
Cylinder::~Cylinder()
{    
    cout << height<< endl;    
}
float Cylinder::area()
{
    return 2*Circle::area()+Circle::line()*height;
}


int main()
{
    Cylinder cy(1,2);
    cout << cy.area() << endl;
    system("pause");
    return 0;
}