如何用C语言编写多人聊天室 具备群聊和私聊功能

要编写一个多人聊天室，具备群聊和私聊功能，你可以使用套接字（socket）编程来实现。下面是一个简单的示例代码，可以作为你开始的参考：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

#define MAX_CLIENTS 10
#define BUFFER_SIZE 1024

typedef struct {
    int client_socket;
    struct sockaddr_in address;
    char username[20];
} Client;

Client clients[MAX_CLIENTS];
int num_clients = 0;

void broadcast_message(const char* message, int sender_socket) {
    for (int i = 0; i < num_clients; i++) {
        if (clients[i].client_socket != sender_socket) {
            send(clients[i].client_socket, message, strlen(message), 0);
        }
    }
}

void handle_client_message(int client_index) {
    char buffer[BUFFER_SIZE];
    int read_size;

    read_size = recv(clients[client_index].client_socket, buffer, BUFFER_SIZE - 1, 0);
    if (read_size > 0) {
        buffer[read_size] = '\0';
        if (buffer[0] == '/') {
            // 私聊功能
            // 实现私聊功能的逻辑
        } else {
            // 群聊功能
            broadcast_message(buffer, clients[client_index].client_socket);
        }
    } else if (read_size == 0) {
        printf("Client disconnected: %s\n", clients[client_index].username);
        close(clients[client_index].client_socket);
        // 移除已断开连接的客户端
        for (int i = client_index; i < num_clients-1; i++) {
            clients[i] = clients[i+1];
        }
        num_clients--;
    }
}

int main() {
    int server_socket, new_socket;
    struct sockaddr_in server_address, client_address;
    socklen_t address_len;

    // 创建套接字
    server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket == -1) {
        perror("Failed to create socket");
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址和端口
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = INADDR_ANY;
    server_address.sin_port = htons(8888);

    // 绑定套接字到服务器地址和端口
    if (bind(server_socket, (struct sockaddr*)&server_address, sizeof(server_address)) < 0) {
        perror("Bind failed");
        exit(EXIT_FAILURE);
    }

    // 监听连接请求
    if (listen(server_socket, MAX_CLIENTS) < 0) {
        perror("Listen failed");
        exit(EXIT_FAILURE);
    }

    printf("Chat server started on port 8888\n");

    while (1) {
        // 接受客户端连接请求
        address_len = sizeof(client_address);
        new_socket = accept(server_socket, (struct sockaddr*)&client_address, &address_len);
        if (new_socket < 0) {
            perror("Accept failed");
            exit(EXIT_FAILURE);
        }

        // 获取客户端的用户名
        char username[20];
        read(new_socket, username, sizeof(username));
        printf("New connection: %s\n", username);

        // 将客户端添加到客户端列表中
        Client new_client;
        new_client.client_socket = new_socket;
        new_client.address = client_address;
        strcpy(new_client.username, username);
        clients[num_clients++] = new_client;

        // 向所有客户端广播新用户加入的消息
        char join_message[50];
        sprintf(join_message, "%s has joined the chat\n", username);
        broadcast_message(join_message, new_socket);

        // 创建新的线程来处理客户端消息
        // 这里可以使用多线程或多进程来处理并发连接
        // 注意：线程/进程的创建和管理需要根据具体的操作系统和编程环境进行
        // 这里只提供了基本的逻辑示例
        handle_client_message(num_clients - 1);
    }

    return 0;
}

上述代码实现了一个简单的多人聊天室，允许客户端进行群聊和私聊。你可以根据需求进行进一步的修改和扩展。请注意，上述代码中只给出了基本的实现逻辑，实际的实现可能需要更多的错误处理和线程/进程管理。同时，还需要考虑并发连接和消息的同步问题。