//观察者
class Observer  
{
public:
    Observer() {}
    virtual ~Observer() {}
    virtual void Update() {} 
};
//博客
class Blog  
{
public:
    Blog() {}
    virtual ~Blog() {}
    void Attach(Observer *observer) { m_observers.push_back(observer); }     //添加观察者
    void Remove(Observer *observer) { m_observers.remove(observer); }        //移除观察者
    void Notify() //通知观察者
    {
        list<Observer*>::iterator iter = m_observers.begin();
        for(; iter != m_observers.end(); iter++)
            (*iter)->Update();
    }
    virtual void SetStatus(string s) { m_status = s; } //设置状态
    virtual string GetStatus() { return m_status; }    //获得状态
private:
    list<Observer* > m_observers; //观察者链表
protected:
    string m_status; //状态
};

//具体博客类
class BlogCSDN : public Blog
{
private:
    string m_name; //博主名称
public:
    BlogCSDN(string name): m_name(name) {}
    ~BlogCSDN() {}
    void SetStatus(string s) { m_status = "CSDN通知 : " + m_name + s; } //具体设置状态信息
    string GetStatus() { return m_status; }
};
//具体观察者
class ObserverBlog : public Observer   
{
private:
    string m_name;  //观察者名称
    Blog *m_blog;   //观察的博客，当然以链表形式更好，就可以观察多个博客
public: 
    ObserverBlog(string name,Blog *blog): m_name(name), m_blog(blog) {}
    ~ObserverBlog() {}
    void Update()  //获得更新状态
    { 
        string status = m_blog->GetStatus();
        cout<<m_name<<"-------"<<status<<endl;
    }
};

//测试案例
int main()
{
    Blog *blog = new BlogCSDN("wuzhekai1985");
    Observer *observer1 = new ObserverBlog("tutupig", blog);
    blog->Attach(observer1);
    blog->SetStatus("发表设计模式C++实现（15）——观察者模式");
    blog->Notify();
    delete blog; delete observer1;
    return 0;
}