1 #include <iostream> 2 #include <string> 3 #include <vector> 4 using namespace std; 5  6 class Memo 7 { 8 public: 9     string state;10     Memo(string state)11     {12         this->state = state;13     }14 };15 16 class Originator17 {18 public:19     string state;20     void setMemo(Memo *memo)21     {22         state = memo->state;23     }24     Memo *createMemo()25     {26         return new Memo(state);27     }28     void show()29     {30         cout << state << endl;31     }32 };    33 34 class Caretaker35 {36 public:37     vector<Memo *> memo;38 public:39     void save(Memo *memo)40     {41         (this->memo).push_back(memo);42     }43     Memo *getState(int i)44     {45         return memo[i];46     }47 };48  49 int main()50 {51     Originator *og = new Originator();52     Caretaker *ct = new Caretaker(); 53 54     og->state = "on";55     og->show();    56     ct->save(og->createMemo());57 58     og->state = "off";59     og->show();60     ct->save(og->createMemo());61 62     og->state = "middle";63     og->show();64     ct->save(og->createMemo());65 66     og->setMemo( ct->getState(1) );67     og->show();68 69     return 0;70 }71 //Result:72 /*73 on74 off75 middle76 off77 */