c++的设计模式之备忘录模式

备忘录模式就是能够存储当前状态，类似于玩游戏的时候可以不断的读档，同时在玩了新的游戏的时候，又可以更新到档案里。

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

//需保存的信息
class Memento
{
	public:
		int m_vitality; //生命值
		int m_attack;   //进攻值
		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;
		}
};
//游戏角色
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()  //保存进度，只与Memento对象交互，并不牵涉到Caretake
		{
			Memento memento(m_vitality, m_attack, m_defense);
			return memento;
		}
		void Load(Memento memento)  //载入进度，只与Memento对象交互，并不牵涉到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; }
};
//保存的进度库
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;
};  

//测试案例
int main()
{
	Caretake caretake;
	GameRole role;
	role.Show();   //初始值
	caretake.Save(role.Save()); //保存状态
	role.Attack();
	role.Show();  //进攻后
	role.Load(caretake.Load(0)); //载入状态
	role.Show();  //恢复到状态0
	return 0;
}