#include <iostream>
#define PI 3.14
using namespace std;
class Circle
{
private:
double radius;
public:
void setRadius(double r);
double area();
double circumference();
};
void Circle::setRadius(double r)
{
radius=r;
}
double Circle::area()
{
return (PI*radius*radius);
}
double Circle::circumference()
{
return (2*PI*radius);
}
int main()
{
double r;
cout<<"请输入旱冰场的半径: ";
cin>>r;
Circle c;
c.setRadius(r);
cout<<"旱冰场的造价为 "<<20*c.area()+35*c.circumference()<<" 元。"<<endl;
return 0;
}
运行结果: