// ***************************************************
// Header file Sphere.h for the class sphereClass.
// ***************************************************
const double PI = 3.14159;
class sphereClass
{
public:
   sphereClass();
   // Default constructor: Creates a sphere and
   // initializes its radius to a default value.
   // Precondition: None.
   // Postcondition: A sphere of radius 1 exists.

   sphereClass(double InitialRadius);
   // Constructor: Creates a sphere and initializes 
   // its radius.
   // Precondition: InitialRadius is the desired 
   // radius.
   // Postcondition: A sphere of radius InitialRadius 
   // exists.

   void SetRadius(double NewRadius);
   // Sets (alters) the radius of an existing sphere.
   // Precondition: NewRadius is the desired radius.
   // Postcondition: The sphereÕs radius is NewRadius.

   double Radius() const;
   // Determines a sphere's radius.
   // Precondition: None.
   // Postcondition: Returns the radius.

   double Diameter() const;
   // Determines a sphere's diameter.
   // Precondition: None.
   // Postcondition: Returns the diameter.

   double Circumference() const;
   // Determines a sphere's circumference.
   // Precondition: PI is a named constant.
   // Postcondition: Returns the circumference.

   double Area() const;
   // Determines a sphere's surface area.
   // Precondition: PI is a named constant.
   // Postcondition: Returns the surface area.

   double Volume() const;
   // Determines a sphere's volume.
   // Precondition: PI is a named constant.
   // Postcondition: Returns the volume.

   void DisplayStatistics() const; 
   // Displays statistics of a sphere.
   // Precondition: None.
   // Postcondition: Displays the radius, diameter,
   // circumference, area, and volume.

private:
   double TheRadius;  // the sphereÕs radius
};  // end class
// End of header file.