// Sphere.h

class Sphere
{
 public:
   Sphere();
   ~Sphere();
   
   static int getNumberOfSpheres();
   
 private:
   double myRadius, myDensity, myWeight;
   static int numberOfSpheres;
};

int Sphere::numberOfSpheres = 0;

inline Sphere::Sphere()
{
  myRadius = myDensity = myWeight = 0.0;
  numberOfSpheres++;
}

inline int Sphere::getNumberOfSpheres()
{
  return numberOfSpheres;
}

inline Sphere::~Sphere()
{
  numberOfSpheres--;
}