c08p407b.txt

Data Abstraction & Problem Solving with C++源码

class Sphere
{
public:
// constructors and operations as before
   friend void readSphereData(Sphere& s); 
   friend void writeSphereData(Sphere& s); 
private:
   double theRadius;  // the sphere's radius
};  // end class

class Ball: public Sphere
{
public:
   Ball();
   Ball(double initialRadius, 
        const string initialName);
   void getName(string currentName) const;
   void setName(const string newName);
   void resetBall(double newRadius, 
                  const string newName);
   void displayStatistics() const;
private:
   string theName;  // the ball's name
};  // end class