旱冰场的维护

#include <iostream>#define PI 3.14using 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：