好的，我正在尝试编写一个程序，它可以接收密码和用户名并将它们存储在一个文件中（我还没有写它们写入文件的部分，稍后会写），但是我的代码中读取文件的部分导致它无法工作（没有输出）即使它在VS代码中编译没有错误。老实说，我也不完全理解我写的东西（我只是看了一个youtube视频），所以我一定是错过了一些代码。为了获得更多信息，我使用C++20和clang ++作为我的编译器。我把我的代码贴在下面以供参考。

#include <iostream>
#include <cstdio>
#include <vector>
#include <fstream>

using namespace::std;

class user {
    private:
        string username;
        string password;
    public:
        user(string user, string pass) {
            username = user;
            password = pass;
        }
        void SetUsername(string user) {
            username = user;
        }
        void SetPassword(string pass) {
            password = pass;
        }
        void ChangeUsername(string user) {
            username = user;
        }
        void ChangePassword(string pass) {
            password = pass;
        }
        string GetUsername() {
            return username;
        }
        string GetPassword() {
            return password;
        }
        
        

};

int main() {
    string listUsernames[1000];
    string listPasswords[1000];
    vector <user>list;
    string username;
    string password;
    string prompt;
    bool loginSuccess = false;
    bool success = false;
    int counter = 0;
    int lines = 0;

    /*
    This part is like messsing it up
    Starting from here:
    */
    ifstream file;
    file.open("usernames.txt");
    while(!file.eof()) {
        getline(file, listUsernames[lines]);
        lines++;
    }
    file.close();

    lines = 0;
    file.open("passwords.txt");
    while(!file.eof()) {
        getline(file, listPasswords[lines]);
        lines++;
    }
    file.close();

    for(int i = 0; i < lines; i++) {
        user oldUser(listUsernames[i], listPasswords[i]);
        list.push_back(oldUser);
    }
    /*
    Ending here
    */

    cout << "\tWelcome user! Please choose to login or create an account below.\n";
    do{
    cout << "\tType \"Login\" to login or \"Create\" to create a new account\n";
    cin >> prompt;
        if(prompt == "Login") {
            do{
                cout << "Username: ";
                cin >> username;
                cout << "Password: ";
                cin >> password;

                for(int i = 0; i < list.size(); i++) {
                    if(username == list[i].GetUsername() && password == list[i].GetPassword()) {
                        cout << "Hello " << list[i].GetUsername() << "!\n\n";
                        loginSuccess = true;
                        success = true;
                    }
                }
                if(!loginSuccess) {
                    cout << "Incorrect username or password";
                    counter++;
                    if(counter < 2) {
                        cout << ", please try again.\n";
                    }
                    else {
                        cout << "\nMaybe you should try creating an account! \n";
                    }
                }
            } while(!loginSuccess && counter < 2);
        }
        else if(prompt == "Create") {
            string newUsername;
            string newPassword;
            cout << "What would you like your username to be? Please enter: ";
            cin >> newUsername;
            cout << "What would you like your password to be? Please enter: ";
            cin >> newPassword;  
            user newUser(newUsername, newPassword);
            list.push_back(newUser);
            cout << "Success!\n";
            ofstream myfile;
            myfile.open("usernames");
            myfile << newUsername;
            myfile.close();
            myfile.open("passwords");
            myfile << newPassword;
            myfile.close();
        }
        else {
            cout << "Sorry, that input was not understood\n";
            cout << "Please try again\n";
        }
    } while(!success);
    return 0;
}