C언어 원의 넓이

Circle ver_1.cpp

#include<iostream>
#include<string>
using namespace std;

class Circle
{
private:
        double r, area;
public:
        Circle(){r=2;}
        Circle(double n){r=n;}
        void calcArea(){area=3.14*r*r;}
        void print();
};

void Circle::print()
{
        cout<<"반지름 : "<<r<<endl;
        cout<<"원의 넓이 : "<<area<<endl;
}

void main()
{
        int n;
        Circle cr;
        cr.calcArea();
        cr.print();
        
        cin>>n;
        Circle cr1(n);
        cr1.calcArea();
        cr1.print();
}