1  class base
       2  {
       3   public:
       4   base() {}
       5   virtual ~base() {}
       6   static base *factory (void);
       7  };
       8  
       9  class object : public base
      10  {
      11   public:
      12   object() {}
      13   object (int);
      14   virtual void key_method (void);
      15  };