[行为型模式] 备忘录模式的理解

迷南。 2022-04-11 05:52 191阅读 0赞

\[img\]https://api5.yunpan.360.cn/intf.php?method=Share.getPublicThumbByNid&qid=108635719&nid=13770720612900431&size=800\_600&devtype=web&v=1.0.1&rtick=14676146429127&share\_qid=108635719&sign=35a231a5a118e9bbf5376407af1df7d1&\[/img\]  
\[img\]https://api5.yunpan.360.cn/intf.php?method=Share.getPublicThumbByNid&qid=108635719&nid=14676145749467500&size=800\_600&devtype=web&v=1.0.1&rtick=14676146452631&share\_qid=108635719&sign=3a796c1ee8fa23e38dc0477615a6d7ee&\[/img\]  
\[img\]https://api5.yunpan.360.cn/intf.php?method=Share.getPublicThumbByNid&qid=108635719&nid=14676145739462727&size=800\_600&devtype=web&v=1.0.1&rtick=14676146458843&share\_qid=108635719&sign=7e0b4aad46b013172c95653e58134075&\[/img\]  
  
\[color=red\]\[b\]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  
\[img\]https://api5.yunpan.360.cn/intf.php?method=Share.getPublicThumbByNid&qid=108635719&nid=14676145999492298&size=800\_600&devtype=web&v=1.0.1&rtick=14676146459049&share\_qid=108635719&sign=f81047e343fe2795f96343a552af2e23&\[/img\]