subject.cpp

c++程序

//Subject.cpp

#include "Subject.h" 
#include "Observer.h"

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

typedef string state;

Subject::Subject() 
{ 
	//****在模板的使用之前一定要new，创建 
	_obvs = new list<Observer*>;
}

Subject::~Subject() 
{ 
}

void Subject::Attach(Observer* obv) 
{ 
	_obvs->push_front(obv); 
}

void Subject::Detach(Observer* obv) 
{
	if (obv != NULL) 
		_obvs->remove(obv); 
}

void Subject::Notify() 
{
	list<Observer*>::iterator it;
	it = _obvs->begin();
	for (;it != _obvs->end();it++) 
	{ //关于模板和iterator的用法

		(*it)->Update(this); 
	} 
}

ConcreteSubject::ConcreteSubject() 
{ 
	_st = '\0'; 
}

ConcreteSubject::~ConcreteSubject() 
{ 
}

State ConcreteSubject::GetState() 
{ 
	return _st; 
}

void ConcreteSubject::SetState(const State& st) 
{
	_st = st; 
}