用c语言编写TCP客户端及服务器通讯程序

下面是一个简单的基于TCP协议的客户端和服务器通讯程序示例，使用C语言编写。

服务器端代码：

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

#define SERVER_PORT 8080
#define MAX_MSG_SIZE 1024

int main()
{
    // 创建套接字
    int server_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (server_fd < 0)
    {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    // 绑定地址和端口号
    struct sockaddr_in server_addr;
    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(SERVER_PORT);
    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
    {
        perror("bind");
        exit(EXIT_FAILURE);
    }

    // 监听连接
    if (listen(server_fd, 5) < 0)
    {
        perror("listen");
        exit(EXIT_FAILURE);
    }

    printf("Server started, waiting for client...\n");

    // 接收连接请求并处理
    while (1)
    {
        struct sockaddr_in client_addr;
        socklen_t client_addr_len = sizeof(client_addr);
        int client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_addr_len);
        if (client_fd < 0)
        {
            perror("accept");
            continue;
        }

        printf("Client connected: %s:%d\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

        // 接收客户端消息并打印
        char recv_buf[MAX_MSG_SIZE];
        int recv_len = recv(client_fd, recv_buf, MAX_MSG_SIZE, 0);
        if (recv_len < 0)
        {
            perror("recv");
            close(client_fd);
            continue;
        }

        recv_buf[recv_len] = '\0';
        printf("Received message from client: %s\n", recv_buf);

        // 发送响应消息
        char send_buf[MAX_MSG_SIZE] = "Hello, client!";
        int send_len = send(client_fd, send_buf, strlen(send_buf), 0);
        if (send_len < 0)
        {
            perror("send");
            close(client_fd);
            continue;
        }

        printf("Response message sent to client: %s\n", send_buf);

        // 关闭套接字
        close(client_fd);
    }

    close(server_fd);
    return 0;
}

客户端代码：

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

#define SERVER_ADDR "127.0.0.1"
#define SERVER_PORT 8080
#define MAX_MSG_SIZE 1024

int main()
{
    // 创建套接字
    int client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (client_fd < 0)
    {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    // 连接服务器
    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr(SERVER_ADDR);
    server_addr.sin_port = htons(SERVER_PORT);
    if (connect(client_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
    {
        perror("connect");
        exit(EXIT_FAILURE);
    }

    printf("Connected to server: %s:%d\n", SERVER_ADDR, SERVER_PORT);

    // 发送消息给服务器
    char send_buf[MAX_MSG_SIZE] = "Hello, server!";
    int send_len = send(client_fd, send_buf, strlen(send_buf), 0);
    if (send_len < 0)
    {
        perror("send");
        close(client_fd);
        exit(EXIT_FAILURE);
    }

    printf("Message sent to server: %s\n", send_buf);

    // 接收服务器响应消息并打印
    char recv_buf[MAX_MSG_SIZE];
    int recv_len = recv(client_fd, recv_buf, MAX_MSG_SIZE, 0);
    if (recv_len < 0)
    {
        perror("recv");
        close(client_fd);
        exit(EXIT_FAILURE);
    }

    recv_buf[recv_len] = '\0';
    printf("Received message from server: %s\n", recv_buf);

    // 关闭套接字
    close(client_fd);

    return 0;
}