備忘錄模式就是能夠儲存當前狀態，類似於玩遊戲的時候可以不斷的讀檔，同時在玩了新的遊戲的時候，又可以更新到檔案裡。

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

//需儲存的資訊  
class Memento    
{  
	public:  
		int m_vitality; //生命值  
		int m_attack;   //進攻值  
		int m_defense;  //防守值  
	public:  
		Memento(int vitality, int attack, int defense):   
			m_vitality(vitality),m_attack(attack),m_defense(defense){}  
		Memento& operator=(const Memento &memento)   
		{  
			m_vitality = memento.m_vitality;  
			m_attack = memento.m_attack;  
			m_defense = memento.m_defense;  
			return *this;  
		}  
};  
//遊戲角色  
class GameRole    
{  
	private:  
		int m_vitality;  
		int m_attack;  
		int m_defense;  
	public:  
		GameRole(): m_vitality(100),m_attack(100),m_defense(100) {}  
		Memento Save()  //儲存進度，只與Memento物件互動，並不牽涉到Caretake  
		{   
			Memento memento(m_vitality, m_attack, m_defense);  
			return memento;  
		}  
		void Load(Memento memento)  //載入進度，只與Memento物件互動，並不牽涉到Caretake  
		{  
			m_vitality = memento.m_vitality;  
			m_attack = memento.m_attack;   
			m_defense = memento.m_defense;  
		}  
		void Show() { cout<<"vitality : "<< m_vitality<<", attack : "<< m_attack<<", defense : "<< m_defense<<endl; }  
		void Attack() { m_vitality -= 10; m_attack -= 10;  m_defense -= 10; }  
};  
//儲存的進度庫  
class Caretake    
{  
	public:  
		Caretake() {}  
		void Save(Memento menento) { m_vecMemento.push_back(menento); }  
		Memento Load(int state) { return m_vecMemento[state]; }  
	private:  
		vector<Memento> m_vecMemento;  
};  

//測試案例  
int main()  
{     
	Caretake caretake;  
	GameRole role;   
	role.Show();   //初始值  
	caretake.Save(role.Save()); //儲存狀態  
	role.Attack();     
	role.Show();  //進攻後  
	role.Load(caretake.Load(0)); //載入狀態   
	role.Show();  //恢復到狀態0  
	return 0;  
}