#include <iostream>
#include <conio.h>
using namespace std;

const double PI = 3.14;

void pause()
{
    cout << "Press any key to continue..." << endl;
    _getch();
}

class Circle {

private:

    double radius;

public:

    void set_radius(int r)
    {
        radius = r;
    }

    double get_radius()
    {
        return radius;
    }

    double get_diameter()
    {
        return radius * 2;
    }

    double get_circumference()
    {
        return PI*radius * 2;
    }
};