[IPhone] Observer with Game Development

Introduction
When I develop my game project. I use a global timer to update game scene, and game scene will update all game roles in game scene if need.
Background
After study observer, I think game scene is a observable and it can notify game role to update.
So I implement observer pattern in my game.

UML


Observer Code

class Observable;
class Observer : public NSObject
{
private:
  // --- Add private member --- //
public:
  // --- Add public member --- //
  Observer();
  virtual ~Observer();

  virtual void Update() = 0;
};

typedef set<observer*> SET;

class Observable : public NSObject
{
private:
  // --- Add private member --- //
  SET m_observers;
public:
  // --- Add public member --- //
  Observable();
  virtual~Observable();

  void RegisterObserver(Observer *o);
  void RemoveObserver(Observer *o);
  void NotifyObservers();
};
void Observable::RegisterObserver(Observer *o)
{
  m_observers.insert(o);
}
void Observable::RemoveObserver(Observer *o)
{
  m_observers.erase(o);
}

void Observable::NotifyObservers()
{
  SET::reverse_iterator index;
  SET::reverse_iterator end = m_observers.rend();
  for(index = m_observers.rbegin(); index != end; index++)
  {
      ((Observer*)(*index))->Update();
  }
}