c++//派生//20191210

编程实现：设计一个基类shape，从基类派生出圆，从圆派生出圆柱，设计成员函数，输出圆的面积和圆柱的体积

/*作业：
编程实现：设计一个基类shape，从基类派生出圆，从圆派生出圆柱，设计成员函数，输出圆的面积和圆柱的体积
*/
#include<iostream>
using namespace std;
class shape
{
public:
	shape() {}
};
class circle :public shape
{
private:
	float r;
public:
	circle(float r=0) :r(r) {}
	double circle_area()
	{
		return 3.1415 * r * r;
	}
	void print_area()
	{
		cout << "圆的面积是:" << circle_area();
	}
};
class circular_column :public circle
{
private:
	float h;
public:
	circular_column(float r, float h) :circle(r),h(h){}
	float volumn()
	{
		return circle_area() * h;
	}
	void print_volumn()
	{
		cout << "圆柱的体积是:" << volumn();
	}
};
float main()
{
	float r, h;
	cout << "请输入圆的半径:";
	cin >> r;
	cout << "请输入圆柱的高:";
	cin >> h;
	circular_column v(r,h);
	v.print_area();
	cout << endl;
	v.volumn();
	v.print_volumn();
}