Windows下实现 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

下面是一个简单的 C++ 实现，用于实现 Windows 下的 TCP 服务器/客户端多人聊天室，包括客户端用户的登录和账号密码的读取。

### 服务器端

#include <iostream>
#include <winsock2.h>
#include <windows.h>
#include <vector>
#include <fstream>
#include <sstream>

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

using namespace std;

struct User {
    string name;
    string password;
};

vector<User> users;

void LoadUsers() {
    ifstream file("users.txt");
    string line;
    while (getline(file, line)) {
        stringstream ss(line);
        string name, password;
        ss >> name >> password;
        users.push_back({name, password});
    }
}

bool CheckUser(string name, string password) {
    for (auto user : users) {
        if (user.name == name && user.password == password) {
            return true;
        }
    }
    return false;
}

int main() {
    LoadUsers();
    WSADATA wsaData;
    SOCKET serverSocket, clientSocket;
    SOCKADDR_IN serverAddr, clientAddr;
    int port = 12345;
    char buffer[1024];

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        cout << "WSAStartup failed!" << endl;
        return 1;
    }

    serverSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (serverSocket == INVALID_SOCKET) {
        cout << "Create socket failed!" << endl;
        return 1;
    }

    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(port);
    serverAddr.sin_addr.s_addr = INADDR_ANY;

    if (bind(serverSocket, (SOCKADDR*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
        cout << "Bind socket failed!" << endl;
        closesocket(serverSocket);
        return 1;
    }

    listen(serverSocket, SOMAXCONN);
    cout << "Server started!" << endl;

    while (true) {
        int clientAddrLen = sizeof(clientAddr);
        clientSocket = accept(serverSocket, (SOCKADDR*)&clientAddr, &clientAddrLen);
        if (clientSocket == INVALID_SOCKET) {
            cout << "Accept failed!" << endl;
            closesocket(serverSocket);
            return 1;
        }

        cout << "Client connected: " << inet_ntoa(clientAddr.sin_addr) << ":" << ntohs(clientAddr.sin_port) << endl;

        while (true) {
            int result = recv(clientSocket, buffer, sizeof(buffer), 0);
            if (result == SOCKET_ERROR || result == 0) {
                cout << "Client disconnected: " << inet_ntoa(clientAddr.sin_addr) << ":" << ntohs(clientAddr.sin_port) << endl;
                closesocket(clientSocket);
                break;
            }

            string message(buffer, result);
            if (message.find("login") == 0) {
                stringstream ss(message.substr(6));
                string name, password;
                ss >> name >> password;
                if (CheckUser(name, password)) {
                    string response = "Login success!";
                    send(clientSocket, response.c_str(), response.size() + 1, 0);
                } else {
                    string response = "Login failed!";
                    send(clientSocket, response.c_str(), response.size() + 1, 0);
                }
            } else {
                cout << message << endl;
                for (SOCKET i = 0; i < SOMAXCONN; i++) {
                    if (i != serverSocket && i != clientSocket) {
                        send(i, message.c_str(), message.size() + 1, 0);
                    }
                }
            }
        }
    }

    closesocket(serverSocket);
    WSACleanup();
    return 0;
}

### 客户端

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

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

using namespace std;

int main() {
    WSADATA wsaData;
    SOCKET clientSocket;
    SOCKADDR_IN serverAddr;
    int port = 12345;
    char buffer[1024];
    string username, password;

    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        cout << "WSAStartup failed!" << endl;
        return 1;
    }

    clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (clientSocket == INVALID_SOCKET) {
        cout << "Create socket failed!" << endl;
        return 1;
    }

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

    if (connect(clientSocket, (SOCKADDR*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
        cout << "Connect failed!" << endl;
        closesocket(clientSocket);
        return 1;
    }

    cout << "Enter your username: ";
    getline(cin, username);
    cout << "Enter your password: ";
    getline(cin, password);

    string loginMessage = "login " + username + " " + password;
    send(clientSocket, loginMessage.c_str(), loginMessage.size() + 1, 0);

    while (true) {
        string message;
        getline(cin, message);
        message = username + ": " + message;
        send(clientSocket, message.c_str(), message.size() + 1, 0);
    }

    closesocket(clientSocket);
    WSACleanup();
    return 0;
}

以上代码仅作为示例，实际场景中可能有更复杂的需求。在实际应用中，还需要考虑网络安全等问题。