Item 29. Virtual Constructionors and prototype
Virtual Constructors? C No Virtual Construction This concept. But in some cases this feature, that is, an object that can be created in the same dynamic type with the pointer during polymorphism. Since it is a polymorphism, we must consider the virtual function. Is it possible to call the constructor in the virtual function? Yes, this is the prototype in the design mode: a virtual member function of a clone (). Class meal {public: virtual ~ meal (); Virtual void Eat () = 0; Virtual meal * clone () const = 0; // ...};
Class spaghetti: public meal {public: spaghetti (const spaghetti &); // copy ctor void Eat (); spaghetti * clone () const {return new spaghetti (* this);} // call copy ctor // ... }
Const meal * m = new spaghetti; meal * mymeal = m-> clone ();
Item 30. Factory Method Oh, "Design Mode" book is more detailed.
