C语言实现scoket 编程

C语言可以通过使用socket库来实现socket编程，下面是一个简单的示例程序：

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

#define PORT 8888

int main(int argc, char const *argv[]) {
    int server_fd, client_fd;
    struct sockaddr_in server_addr, client_addr;
    char buffer[1024] = {0};
    int valread;

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

    // 设置socket地址
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(PORT);

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

    // 监听socket
    if (listen(server_fd, 3) < 0) {
        perror("listen failed");
        exit(EXIT_FAILURE);
    }

    // 接受客户端连接
    socklen_t client_addr_len = sizeof(client_addr);
    if ((client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_addr_len)) < 0) {
        perror("accept failed");
        exit(EXIT_FAILURE);
    }

    // 读取客户端数据
    valread = read(client_fd, buffer, 1024);
    printf("%s\n", buffer);

    // 发送响应数据
    char *hello = "Hello from server";
    send(client_fd, hello, strlen(hello), 0);
    printf("Hello message sent\n");

    // 关闭socket
    close(client_fd);
    close(server_fd);

    return 0;
}

这是一个简单的服务器程序，它会监听8888端口，并在接收到客户端连接后，读取客户端发送的数据并回复一条消息。你可以使用telnet命令来测试该程序：

$ telnet localhost 8888
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Hello from client
Hello message sent
Connection closed by foreign host.

其中，telnet命令会连接到本地的8888端口，并发送一条消息。程序会读取这条消息并回复一条"Hello from server"的消息。