备忘录模式
备忘录模式
[实验任务一]：多次撤销
改进课堂上的“用户信息操作撤销”实例，使得系统可以实现多次撤销（可以使用HashMap、ArrayList等集合数据结构实现）。
1. 类图：
2. 源代码：
#include <iostream>
#include <list>
#include <string>
using namespace std;
// 备忘录类
class Memento {
private:
string accountInfo;
string passwordInfo;
public:
Memento(string account, string password) : accountInfo(account), passwordInfo(password) {}
string getAccountInfo() const { return accountInfo; }
string getPasswordInfo() const { return passwordInfo; }
};
// 原始数据类
class UserInfoDTO {
private:
string account;
string password;
public:
void setAccount(string account) { this->account = account; }
void setPassword(string password) { this->password = password; }
string getAccount() const { return account; }
string getPassword() const { return password; }
Memento* saveMemento() {
return new Memento(account, password);
}
void restoreMemento(Memento* memento) {
account = memento->getAccountInfo();
password = memento->getPasswordInfo();
}
void show() {
cout << "Account: " << account << endl;
cout << "Password: " << password << endl;
}
};
// 管理者类
class Caretaker {
private:
list<Memento*> mementoList;
public:
void setMemento(Memento* memento) {
mementoList.push_front(memento);
}
Memento* getMemento() {
if (!mementoList.empty()) {
Memento* memento = mementoList.front();
mementoList.pop_front();
return memento;
}
return nullptr;
}
};
int main() {
UserInfoDTO* user = new UserInfoDTO();
Caretaker* caretaker = new Caretaker();
user->setAccount("张三");
user->setPassword("12345678");
cout << "状态一:" << endl;
user->show();
caretaker->setMemento(user->saveMemento());
cout << "-----------------------------" << endl;
user->setAccount("李四");
user->setPassword("6666666");
cout << "状态二:" << endl;
user->show();
caretaker->setMemento(user->saveMemento());
cout << "-----------------------------" << endl;
user->setAccount("王五");
user->setPassword("88888888");
cout << "状态三:" << endl;
user->show();
caretaker->setMemento(user->saveMemento());
cout << "-----------------------------" << endl;
user->restoreMemento(caretaker->getMemento());
cout << "回到状态二:" << endl;
user->show();
cout << "-----------------------------" << endl;
user->restoreMemento(caretaker->getMemento());
cout << "回到状态一:" << endl;
user->show();
cout << "-----------------------------" << endl;
delete user;
delete caretaker;
return 0;
}
代码：
3. 注意编程规范。
