观察者模式——三英雄战吕布

观察者模式：

被观察者：吕布

观察者：张飞，关羽，刘备

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

class SubjectPeople;
class ObserverPeople
{
public:
    virtual void Action()=0;
};

class SubjectPeople
{
public:
    virtual void RegisterPeople(ObserverPeople* ob) = 0;
    virtual void RemovePeople(ObserverPeople* ob) = 0;
    virtual void NotifyPeople() = 0;
};

class LvBuSubject:public SubjectPeople
{
protected:
    list<ObserverPeople *> OP;

public:
    void RegisterPeople(ObserverPeople* ob)
    {
        OP.push_back(ob);
    }

    void RemovePeople(ObserverPeople* ob)
    {
        list<ObserverPeople*>::iterator it = OP.begin();
        while (it!=OP.end())
        {
            if (*it==ob)
            {
                OP.remove(*it);
                return ;
            }
            it++;
        }
    }

    void NotifyPeople()
    {
        list<ObserverPeople*>::iterator it = OP.begin();
        while (it!=OP.end())
        {
            (*it)->Action();
            it++;
        }
    }

};


class GuanYuOberver:public ObserverPeople
{
public:
    GuanYuOberver(SubjectPeople*op):sp(*op)
    {
        sp.RegisterPeople(this);
    }

public:
    void Action()
    {
        cout<<"关羽给吕布一刀"<<endl;
    }

protected:
    SubjectPeople& sp;
};

class ZhangFeiOberver:public ObserverPeople
{
public:
    ZhangFeiOberver(SubjectPeople*op):sp(*op)
    {
        sp.RegisterPeople(this);
    }

public:
    void Action()
    {
        cout<<"张飞给吕布一杖"<<endl;
    }

protected:
    SubjectPeople& sp;
};

class LiuBeiOberver:public ObserverPeople
{
public:
    LiuBeiOberver(SubjectPeople*p):sp(*p)
    {
        sp.RegisterPeople(this);
    }

public:
    void Action()
    {
        cout<<"刘备给吕布一刀"<<endl;
    }

protected:
    SubjectPeople& sp;
};



int main()
{
    LvBuSubject lvb;
    GuanYuOberver gy(&lvb);
    LiuBeiOberver liub(&lvb);
    ZhangFeiOberver zf(&lvb);

    lvb.NotifyPeople();
    return 0;
}