c++day7

#include <iostream>
#include <vector>
#include <string>

using namespace std;

// 用户信息结构体
struct User {
    string username;
    string password;
};

// 全局用户数据库（实际应用应使用数据库）
vector<User> users;

// 注册功能实现
void registerUser() {
    User newUser;
    
    cout << "请输入用户名: ";
    cin >> newUser.username;
    
    // 检查用户名重复
    for (const auto& user : users) {
        if (user.username == newUser.username) {
            cout << "用户名已存在！" << endl;
            return;
        }
    }
    
    cout << "请输入密码: ";
    cin >> newUser.password;
    
    users.push_back(newUser);
    cout << "注册成功！" << endl;
}

// 登录功能实现
void loginUser() {
    string inputUsername, inputPassword;
    
    cout << "请输入用户名: ";
    cin >> inputUsername;
    cout << "请输入密码: ";
    cin >> inputPassword;
    
    for (const auto& user : users) {
        if (user.username == inputUsername && user.password == inputPassword) {
            cout << "登录成功！欢迎 " << inputUsername << endl;
            return;
        }
    }
    
    cout << "登录失败！用户名或密码错误" << endl;
}

// 主菜单界面
int main() {
    int choice;
    
    while (true) {
        cout << "
===== 本地用户系统 =====";
        cout << "
1. 注册
2. 登录
3. 退出";
        cout << "
请选择操作: ";
        
        cin >> choice;
        
        switch (choice) {
            case 1:
                registerUser();
                break;
            case 2:
                loginUser();
                break;
            case 3:
                cout << "退出系统" << endl;
                return 0;
            default:
                cout << "无效选项，请重新选择" << endl;
        }
    }
    
    return 0;
}