实现 C/C++下TCP, 服务器/客户端 "多人聊天室",客户端用户需要登陆，用户账号密码用txt保存并读取，要求在windows下运行

实现一个基于 TCP 的多人聊天室，需要分为服务器端和客户端两个部分。

服务器端：

服务器端需要监听指定端口，等待客户端连接。当有新的客户端连接时，服务器需要为其分配一个唯一的 ID，并且将其添加到客户端列表中。

服务器需要维护一个聊天室的状态，比如在线用户列表和聊天记录等。当有用户发送消息时，服务器需要将消息广播给所有在线用户。

客户端：

客户端需要先进行登录验证，可以通过读取本地存储的账号密码文本文件进行验证。如果验证通过，客户端可以连接到服务器，并加入聊天室。

客户端可以发送消息给服务器，服务器会将其广播给所有在线用户。客户端也需要接收其他用户发送的消息，并将其显示在界面上。

下面是一个 C++ 实现的简单示例代码，仅供参考：

服务器端代码：

#include <iostream>
#include <vector>
#include <string>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

using namespace std;

const int BUF_SIZE = 1024;
const int MAX_CLIENTS = 10;

struct Client {
    int id;
    SOCKET socket;
    sockaddr_in addr;
};

vector<Client> clients;
int nextId = 1;

void broadcastMessage(const string& message, int senderId) {
    cout << "Broadcasting message: " << message << endl;
    for (auto& client : clients) {
        if (client.id != senderId) {
            send(client.socket, message.c_str(), message.length(), 0);
        }
    }
}

void handleClient(Client& client) {
    char buf[BUF_SIZE];
    while (true) {
        int len = recv(client.socket, buf, BUF_SIZE, 0);
        if (len <= 0) {
            // client disconnected
            cout << "Client " << client.id << " disconnected." << endl;
            closesocket(client.socket);
            clients.erase(remove(clients.begin(), clients.end(), client), clients.end());
            break;
        }

        buf[len] = '\0';
        string message(buf);
        cout << "Received message from client " << client.id << ": " << message << endl;
        broadcastMessage(message, client.id);
    }
}

int main() {
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);

    SOCKET listener = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    addr.sin_port = htons(12345);

    bind(listener, (sockaddr*)&addr, sizeof(addr));
    listen(listener, MAX_CLIENTS);

    cout << "Server started. Listening on port 12345..." << endl;

    while (true) {
        SOCKET clientSocket = accept(listener, NULL, NULL);
        Client client{ nextId++, clientSocket };
        getpeername(clientSocket, (sockaddr*)&client.addr, (int*)sizeof(client.addr));
        clients.push_back(client);
        cout << "Client " << client.id << " connected from " << inet_ntoa(client.addr.sin_addr) << endl;
        CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)handleClient, (LPVOID)&client, 0, NULL);
    }

    WSACleanup();
    return 0;
}

客户端代码：

#include <iostream>
#include <string>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

using namespace std;

const int BUF_SIZE = 1024;

bool login(SOCKET socket) {
    string username, password;
    cout << "Please enter your username: ";
    cin >> username;
    cout << "Please enter your password: ";
    cin >> password;

    // TODO: read username and password from file and compare with input

    string message = "LOGIN " + username + " " + password;
    send(socket, message.c_str(), message.length(), 0);

    char buf[BUF_SIZE];
    int len = recv(socket, buf, BUF_SIZE, 0);
    if (len <= 0) {
        cout << "Server disconnected." << endl;
        return false;
    }

    buf[len] = '\0';
    string response(buf);
    if (response == "OK") {
        cout << "Login succeeded." << endl;
        return true;
    } else {
        cout << "Login failed: " << response << endl;
        return false;
    }
}

void receiveMessages(SOCKET socket) {
    char buf[BUF_SIZE];
    while (true) {
        int len = recv(socket, buf, BUF_SIZE, 0);
        if (len <= 0) {
            cout << "Server disconnected." << endl;
            break;
        }

        buf[len] = '\0';
        string message(buf);
        cout << "Received message: " << message << endl;
    }
}

int main() {
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);

    SOCKET socketClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    sockaddr_in serverAddr;
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(12345);
    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");

    connect(socketClient, (sockaddr*)&serverAddr, sizeof(serverAddr));

    if (!login(socketClient)) {
        return 0;
    }

    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)receiveMessages, (LPVOID)&socketClient, 0, NULL);

    string message;
    while (true) {
        cout << "> ";
        getline(cin, message);
        send(socketClient, message.c_str(), message.length(), 0);
    }

    WSACleanup();
    return 0;
}