基于c语言使用socket编程实现简易聊天室

实现简易聊天室需要以下步骤:

1. 创建服务器

使用socket函数创建服务器，使用bind函数将服务器绑定到指定的IP地址和端口号。使用listen函数监听客户端连接请求。

2. 接受客户端连接请求

使用accept函数接受客户端连接请求，创建一个新的套接字用于与客户端通信。

3. 接收和发送消息

使用recv函数接收客户端发送的消息，使用send函数将消息发送给客户端。

4. 处理多个客户端

使用多线程或多进程处理多个客户端连接请求，每个线程或进程处理一个客户端连接请求。

下面是一个简单的示例代码：

服务器端：

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

#define MAX_CLIENTS 10
#define BUFFER_SIZE 1024

int clients[MAX_CLIENTS];
int num_clients = 0;

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void *client_handler(void *arg)
{
    int client_fd = *(int *)arg;
    char buffer[BUFFER_SIZE];
    int nbytes;

    while ((nbytes = recv(client_fd, buffer, BUFFER_SIZE, 0)) > 0) {
        buffer[nbytes] = '\0';
        printf("Client[%d]: %s", client_fd, buffer);

        pthread_mutex_lock(&mutex);
        for (int i = 0; i < num_clients; i++) {
            if (clients[i] != client_fd) {
                send(clients[i], buffer, nbytes, 0);
            }
        }
        pthread_mutex_unlock(&mutex);
    }

    pthread_mutex_lock(&mutex);
    for (int i = 0; i < num_clients; i++) {
        if (clients[i] == client_fd) {
            for (int j = i; j < num_clients - 1; j++) {
                clients[j] = clients[j + 1];
            }
            num_clients--;
            break;
        }
    }
    pthread_mutex_unlock(&mutex);

    close(client_fd);
    printf("Client[%d] exit\n", client_fd);
    return NULL;
}

int main(int argc, char *argv[])
{
    int server_fd, client_fd;
    struct sockaddr_in server_addr, client_addr;
    socklen_t client_len;

    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(6666);

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("bind");
        exit(EXIT_FAILURE);
    }

    if (listen(server_fd, MAX_CLIENTS) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }

    printf("Server start listening on port %d...\n", ntohs(server_addr.sin_port));

    while (1) {
        client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_len);
        if (client_fd < 0) {
            perror("accept");
            continue;
        }

        pthread_t tid;
        pthread_create(&tid, NULL, client_handler, &client_fd);
        pthread_detach(tid);

        pthread_mutex_lock(&mutex);
        clients[num_clients++] = client_fd;
        pthread_mutex_unlock(&mutex);

        printf("Client[%d] connected\n", client_fd);
    }

    close(server_fd);
    return 0;
}

客户端：

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

#define BUFFER_SIZE 1024

int main(int argc, char *argv[])
{
    int client_fd;
    struct sockaddr_in server_addr;
    char buffer[BUFFER_SIZE];
    int nbytes;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s <server_ip_address>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    client_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (client_fd < 0) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr(argv[1]);
    server_addr.sin_port = htons(6666);

    if (connect(client_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("connect");
        exit(EXIT_FAILURE);
    }

    while (1) {
        fgets(buffer, BUFFER_SIZE, stdin);
        nbytes = strlen(buffer);
        send(client_fd, buffer, nbytes, 0);
    }

    close(client_fd);
    return 0;
}

注意：上述代码仅为示例代码，没有做错误处理和安全性检查，请勿直接使用于生产环境。