求旱冰场造价[自己改编]

#include <iostream>using namespace std;const int M=20;const int N=35;class Circle{public:    double radius;    double area;    double circumference;    void setRadius(double);};void Circle::setRadius(double a){    area=3.14*a*a;    circumference=3.14*2*a;}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"<<M*c.area+N*c.circumference<<"元"<<endl;    return 0;}

示例图片：

心得体会：喜欢胡玩，在老师基础上改变的，感觉比老师的还容易理解。求旱冰场造价[自己改编]