class Chicken () : public Bird { public: int nWings = 2; int nLegs = 2; int bFlight = FALSE; void Cluck () {} } class Hen () : public Chicken { public: void LayEggs () {} } class Cock () : public Chicken { public: void Cockadoodledoo () {} } void main () { Chicken* pClucker; // Chicken pointers can be used with Chickens, Hens and Cocks pClucker = new Hen; // create a Hen
// The functions Cockadoodledoo (), Cluck (), and LayEggs () are not available at this scope. // They are within a different namespace. Cluck (); // This function call will fail, there is no Cluck () in this namespace. LayEggs (); // This function call will fail, there is no LayEggs () in this namespace.
// These function calls will succeed, because they are being called within a different namespace. pClucker -> Cluck (); // you can call a Chicken function through a Chicken pointer pClucker -> LayEggs (); // you can call a Hen function through a Chicken pointer
// If we define Cluck () outside the context of a Chicken... void Cluck () {} // ...this function call will now succeed. Cluck ();
// Note that these two function calls... pClucker -> Cluck (); Cluck ();
// Now do two different things, because they are being called from different namespaces; // the Chicken namespace, and the main () namespace. }