设计模式15：观察者模式【行为型】

#include <iostream>
#include <list>
using namespace std;

//
struct IObserver
{
public:
	virtual ~IObserver() { }

	virtual void Update() = 0;
};

class CObserver : public IObserver
{
public:
	CObserver(string name) : m_name(name) { }
	virtual ~CObserver() { }

	virtual void Update() { cout<<m_name.c_str()<<" observer update."<<endl; }
	
private: 
	string m_name;
};

class CBlog 
{
public:
	void AddObserver(IObserver *pObserver) { m_pObserverList.push_back(pObserver); }
	void RemoveObserver(IObserver *pObserver) { m_pObserverList.remove(pObserver); }

	void Notify()
	{
		list<IObserver*>::iterator ite = m_pObserverList.begin();
		for(; m_pObserverList.end() != ite; ite++)
		{
			(*ite)->Update();
		}
	}
private:
	list<IObserver*> m_pObserverList;
};

//
void main()
{
	CBlog blog;
	
	CObserver observerA("AAA");
	CObserver observerB("BBB");

	blog.AddObserver(&observerA);
	blog.AddObserver(&observerB);

	blog.Notify();
}