5.23打卡

#include <bits/stdc++.h>
using namespace std;
const float PI=3.141593;
const float FENCE_PRICE=35;
const float CONCRETE_PRICE=20;
class Circle
{
    public:
        Circle(float r);
        float circumference();
        float area();
    private:
            float radius;
};
Circle::Circle(float r)
{
    radius=r;
}
float Circle::circumference()
{
    return 2*PI*radius;
}
float Circle::area()
{
    return PI*radius*radius;
}
int main()
{
    float radius;
    cin>>radius;
    Circle pool(radius);
    Circle poolRim(radius+3);
    float fenceCost=poolRim.circumference()*FENCE_PRICE;
    cout<<"Fencing Cost is $"<<fenceCost<<endl;
    float concreteCost=(poolRim.area()-pool.area())*CONCRETE_PRICE;
    cout<<"Concrete Cost is $ "<<concreteCost<<endl;
    return 0;
}