// File: ex5-4.cpp

#include <iostream>
using namespace std;

class Circle
{
private:
    double radius;
    static unsigned numCircles;
public:
    Circle(double r = 1.0);
    ~Circle();
    static void print_numCircles();
    static void resetNumCircles();
};

unsigned Circle::numCircles = 0 ;

Circle::Circle(double r) : radius(r)
{
    numCircles++;
}

Circle::~Circle()
{
    numCircles--;
}
void Circle::print_numCircles()
{
    cout << "number of Circles = " << numCircles << endl;
}

void Circle::resetNumCircles()
{
    numCircles = 0;
}

int main()
{
    Circle c1(5.);
    Circle::print_numCircles();
    Circle c2(4.);
    Circle::print_numCircles();
    Circle::resetNumCircles();
    Circle::resetNumCircles();
    Circle::print_numCircles();
    Circle c3(1.);
    Circle::print_numCircles();
}