c语言写一个聊天室

要实现一个聊天室，需要使用网络编程技术。下面是一个简单的 C 语言聊天室的实现：

1. 客户端代码：

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

#define BUF_SIZE 100
#define NAME_SIZE 20

void error_handling(char *message);
void *send_msg(void *arg);
void *recv_msg(void *arg);

char name[NAME_SIZE] = "[DEFAULT]";
char msg[BUF_SIZE];

int main(int argc, char *argv[]) {
    int sock;
    struct sockaddr_in serv_addr;
    pthread_t snd_thread, rcv_thread;
    void *thread_return;

    if (argc != 4) {
        printf("Usage: %s <IP> <port> <name>\n", argv[0]);
        exit(1);
    }

    sprintf(name, "[%s]", argv[3]);
    sock = socket(PF_INET, SOCK_STREAM, 0);
    if (sock == -1)
        error_handling("socket() error");

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = inet_addr(argv[1]);
    serv_addr.sin_port = htons(atoi(argv[2]));

    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)
        error_handling("connect() error");

    pthread_create(&snd_thread, NULL, send_msg, (void *)&sock);
    pthread_create(&rcv_thread, NULL, recv_msg, (void *)&sock);

    pthread_join(snd_thread, &thread_return);
    pthread_join(rcv_thread, &thread_return);

    close(sock);
    return 0;
}

void *send_msg(void *arg) {
    int sock = *((int *)arg);
    char name_msg[NAME_SIZE + BUF_SIZE];

    while (1) {
        fgets(msg, BUF_SIZE, stdin);
        if (!strcmp(msg, "q\n") || !strcmp(msg, "Q\n")) {
            close(sock);
            exit(0);
        }

        sprintf(name_msg, "%s %s", name, msg);
        write(sock, name_msg, strlen(name_msg));
    }

    return NULL;
}

void *recv_msg(void *arg) {
    int sock = *((int *)arg);
    char name_msg[NAME_SIZE + BUF_SIZE];
    int str_len;

    while (1) {
        str_len = read(sock, name_msg, NAME_SIZE + BUF_SIZE - 1);
        if (str_len == -1)
            return (void *)-1;
        name_msg[str_len] = 0;
        fputs(name_msg, stdout);
    }

    return NULL;
}

void error_handling(char *message) {
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}

2. 服务器端代码：

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

#define BUF_SIZE 100
#define MAX_CLNT 256

void error_handling(char *message);
void *handle_clnt(void *arg);
void send_msg(char *msg, int len);
void error_handling(char *message);

int clnt_cnt = 0;
int clnt_socks[MAX_CLNT];
pthread_mutex_t mutex;

int main(int argc, char *argv[]) {
    int serv_sock, clnt_sock;
    struct sockaddr_in serv_addr, clnt_addr;
    int clnt_addr_size;
    pthread_t t_id;

    if (argc != 2) {
        printf("Usage: %s <port>\n", argv[0]);
        exit(1);
    }

    pthread_mutex_init(&mutex, NULL);

    serv_sock = socket(PF_INET, SOCK_STREAM, 0);
    if (serv_sock == -1)
        error_handling("socket() error");

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(atoi(argv[1]));

    if (bind(serv_sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)
        error_handling("bind() error");

    if (listen(serv_sock, 5) == -1)
        error_handling("listen() error");

    while (1) {
        clnt_addr_size = sizeof(clnt_addr);
        clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_addr, &clnt_addr_size);

        pthread_mutex_lock(&mutex);
        clnt_socks[clnt_cnt++] = clnt_sock;
        pthread_mutex_unlock(&mutex);

        pthread_create(&t_id, NULL, handle_clnt, (void *)&clnt_sock);
        pthread_detach(t_id);
        printf("Connected client IP: %s \n", inet_ntoa(clnt_addr.sin_addr));
    }

    close(serv_sock);
    return 0;
}

void *handle_clnt(void *arg) {
    int clnt_sock = *((int *)arg);
    int str_len = 0, i;
    char msg[BUF_SIZE];

    while ((str_len = read(clnt_sock, msg, sizeof(msg))) != 0)
        send_msg(msg, str_len);

    pthread_mutex_lock(&mutex);
    for (i = 0; i < clnt_cnt; i++) {
        if (clnt_sock == clnt_socks[i]) {
            while (i++ < clnt_cnt - 1)
                clnt_socks[i] = clnt_socks[i + 1];
            break;
        }
    }
    clnt_cnt--;
    pthread_mutex_unlock(&mutex);
    close(clnt_sock);
    return NULL;
}

void send_msg(char *msg, int len) {
    int i;
    pthread_mutex_lock(&mutex);
    for (i = 0; i < clnt_cnt; i++)
        write(clnt_socks[i], msg, len);
    pthread_mutex_unlock(&mutex);
}

void error_handling(char *message) {
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(1);
}

这个简单的聊天室采用了多线程技术，服务端可以同时处理多个客户端的连接。我们可以编译并运行这两个代码，然后在多个终端中运行客户端程序进行聊天。