TOPIC 12.3.2a
Dividing Source Code for Classes

#ifndef _CIRCLE_H
#define _CIRCLE_H

const float PI=3.14159;

class circle
{
 public:
          // constructors
          circle();                         // default constructor
          circle(const circle &);           // copy constructor

          // member functions
          void   SetRadius(float);
          double Area();

 private:
          // data
          float radius;
};
#endif