#include<iostream>
#include<cmath>
using namespace std;
const double Pi=3.14;
class Circle
{
public:
Circle(double r){
radius=r;
}
double Radius()
{
return radius;
}
~Circle(){}
private:
double radius;
};
class Column : public Circle
{
public:
Column(double r, double h):Circle(r)
{high = h;}
double volume()
{
return high*Pi*pow(Radius(), 2);
}
double surface_area()
{
return 2*Pi*pow(Radius(), 2)+2*Pi*Radius()*high;
}
~Column(){}
private:
double high;
};
int main()
{
double r1,r2,h;
cin >> r1 ;
cin >> r2;
cin >> h;
Column C(r2, h);
cout<< C.volume() << endl;
return 0;
}
请问怎么用圆类的成员函数输出圆的面积,谢谢!