使用C++实现OO观察者模式

来源：互联网发布：淘宝上买黄牛票犯法吗编辑：程序博客网时间：2024/05/19 00:37
// test.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <iostream>#include <vector>#include <string>using namespace std; class observerBase{public:virtual void answer(){};};class subjectBase{public:virtual void register_ob(observerBase *){};virtual void delete_ob(observerBase *){};virtual void ask(){};};class subjectS: public subjectBase{public:    vector<observerBase*> ob_list;    void register_ob(observerBase *ob)    {       ob_list.push_back(ob);       //cout<<"push back"<<endl;     }void delete_ob(observerBase *ob){    for(auto i=ob_list.begin();i!=ob_list.end();){if((*i)==ob){i=ob_list.erase(i);}else{i++;}}}    void ask()    {         cout<<"shoud i do?"<<endl; for(auto i=ob_list.begin();i!=ob_list.end();i++)//auto == vector<observerBase*>::iterator         {              (*i)->answer();              //cout<<"answer"<<endl;         }    }};class devil:public observerBase{public:     devil(subjectBase *i) {         i->register_ob(this);         //cout << "reg"<<endl; }     void answer()     {          cout<<"devil said: fuck u"<<endl;     } void leave(subjectBase *i) {     i->delete_ob(this); cout<<"devil said: I leave!"<<endl; }};class angel: public observerBase{public:     angel(subjectBase *i) {         i->register_ob(this);         //cout << "reg"<<endl; }     void answer()     {          cout<<"angel said: yes, try!"<<endl;     }  void leave(subjectBase *i) {     i->delete_ob(this); cout<<"angel said: I leave!"<<endl; }};class man: public observerBase{public:     man(subjectBase *i) {         i->register_ob(this);         //cout << "reg"<<endl; }     void answer()     {          cout<<"man said : I don't know too!"<<endl;     } void leave(subjectBase *i) {     i->delete_ob(this); cout<<"man said : I left!"<<endl; }};int _tmain(int argc, _TCHAR* argv[]){subjectS i;devil *devil_inst = new devil((subjectBase *)&i);angel *angel_inst = new angel((subjectBase *)&i);man *man_inst  = new man((subjectBase *)&i);i.ask();cout<<"========================"<<endl;man_inst->leave((subjectBase *)&i);i.ask();cout<<"========================"<<endl;devil_inst->leave((subjectBase *)&i);i.ask();delete devil_inst;delete man_inst;delete angel_inst;return 0;}
0 0