备忘录模式（Memento）

#include <iostream>
#include <string>
using namespace std;



class OriginalWord;
class Memento {
public:
    Memento(string strWord):m_strWord(strWord){}
private:
    friend class OriginalWord;
    string GetWords() {
        return m_strWord;
    }
    string m_strWord;
};

class OriginalWord {
public:
    OriginalWord(string myWord):m_strWord(myWord){}
    //存档
    Memento* saveWords() {
        return new Memento(m_strWord);
    }

    //恢复存档
    void recycleWords(Memento *pMemento) {
        m_strWord = pMemento->GetWords();
        cout << "存档恢复成功" << endl;
    }

    //输出文字
    void showWords() {
        cout << m_strWord << endl;
    }
private:
    string m_strWord;
};

//用来设置快照，获得快照
class Caretake {
public:
    void setMemento(Memento* pMem) {
        m_pMemento = pMem;
    }
    Memento* GetMemento() {
        return m_pMemento;
    }
private:
    Memento* m_pMemento;
};
int main() {
    OriginalWord *pWordFst = new OriginalWord("跟着老夏学开发");
    //第一条消息
    cout << "第一个msg" << endl;
    pWordFst->showWords();

    Caretake *pCT = new Caretake;
    pCT->setMemento(pWordFst->saveWords());
    //保存了当前Fst的快照
    cout << "保存了当前Fst的快照" << endl;
    OriginalWord *pWordSec = new OriginalWord("升值加薪就找他");
    cout << "第二个Msg" << endl;
    pWordSec->showWords();
    OriginalWord* pWordThd = new OriginalWord("丁老师好像也不错,");
    cout << "第三个Msg" << endl;
    pWordThd->showWords();
    cout << "我们是在多看看老夏和老丁的新课程，我还是想看看夏老师的新课程"<<endl;
    //当我们需要回溯到某一个状态的时候，我们需要问CareTake对象拿到的快照
    pWordFst->recycleWords(pCT->GetMemento());
    pWordFst->showWords();
    system("pause");
    return 0;
}