[行为型模式] 备忘录模式的理解

迷南。 2022-04-11 05:52 230阅读 0赞

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\[color=red\]\[b\]头文件\[/b\]\[/color\]

//MementoPattern.h
    
    #ifndef MEMENTO_PATTERN_H
    #define MEMENTO_PATTERN_H
    
    #include <Windows.h>
    #include <iostream>
    #include <string>
    using namespace std;
    
    namespace MementoPattern
    {
       
        //备忘者类备份发起者的状态
        class Memento
        {
       
        public:
            //构造的时候备份数据
            Memento(string strState):m_strState(strState){    }
    
            void SetState(string strState){ m_strState = strState; }
    
            friend class Originator;
    
        private:
            string m_strState;
        };
    
        //发起者类备份自己的状态
        class Originator
        {
       
        public:
            //建立备份
            Memento* CreateBackups(){ return new Memento(m_strState); }
    
            //恢复备份内容
            void RestoreBackups(Memento* pMemento)
            {
       
                m_strState = pMemento->m_strState;
            }
    
            //显示状态
            void Show()
            {
       
                cout<<m_strState<<endl;
            }
    
            void SetState(string strState){ m_strState = strState; }
    
        private:
            string m_strState;
        };
    
        //管理者类管理备份
        class Caretaker
        {
       
        public:
            //得到备份
            Memento* GetMemento()
            {
       
                return m_pMemento;
            }
            //设置备份
            void SetMemento(Memento* pMemento)
            {
       
                m_pMemento = pMemento;
            }
    
        private:
            Memento* m_pMemento;
        };
    
        //
        void MementoPattern_Test();
    }
    
    #endif

\[color=red\]\[b\]实现\[/b\]\[/color\]

#include "MementoPattern.h"
    #include <iostream>
    using namespace std;
    
    namespace MementoPattern
    {
       
        //
        void MementoPattern_Test()
        {
       
            //设置和显示状态
            Originator o;
            o.SetState("ON");
            o.Show();
    
            //创建备份
            Memento* m = o.CreateBackups();
    
            //管理备份
            Caretaker c;
            c.SetMemento(m);
    
            //设置和显示状态
            o.SetState("OFF");
            o.Show();
    
            //恢复备份
            m = c.GetMemento();
            o.RestoreBackups(m);
    
            //显示状态
            o.Show();
        }
    }

\[color=red\]\[b\]客户端\[/b\]\[/color\]

#include "MementoPattern.h"
    #include <iostream>
    #include <sstream>
    #include <string>
    #include <list>
    using namespace std;
    using namespace MementoPattern;
    
    void  main()
    {
       
        MementoPattern_Test();
    }

运行结果  
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