用C语言完成socket套接字，实现C/S连接，服务器与客户端可以互相收发数据

下面是一个简单的示例代码，实现了服务器与客户端之间的数据传输。

服务器端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>

#define PORT 8080
#define MAX_BUFFER_SIZE 1024

int main(int argc, char const *argv[]) {
    int server_fd, new_socket, valread;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);
    char buffer[MAX_BUFFER_SIZE] = {0};
    char *hello = "Hello from server";

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

    // 设置 socket 选项
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
        perror("setsockopt failed");
        exit(EXIT_FAILURE);
    }

    // 绑定地址和端口
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);

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

    // 监听连接请求
    if (listen(server_fd, 3) < 0) {
        perror("listen failed");
        exit(EXIT_FAILURE);
    }

    // 等待连接请求
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t *)&addrlen)) < 0) {
        perror("accept failed");
        exit(EXIT_FAILURE);
    }

    // 读取客户端发来的消息
    valread = read(new_socket, buffer, MAX_BUFFER_SIZE);
    printf("Message from client: %s\n", buffer);

    // 向客户端发送消息
    send(new_socket, hello, strlen(hello), 0);
    printf("Hello message sent to client\n");

    return 0;
}

客户端代码：

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

#define PORT 8080
#define MAX_BUFFER_SIZE 1024

int main(int argc, char const *argv[]) {
    int sock = 0, valread;
    struct sockaddr_in serv_addr;
    char *hello = "Hello from client";
    char buffer[MAX_BUFFER_SIZE] = {0};

    // 创建 socket
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        printf("\n Socket creation error \n");
        return -1;
    }

    memset(&serv_addr, '0', sizeof(serv_addr));

    // 配置服务器地址和端口
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);

    // 将 IPv4 地址转换为网络字节序
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        printf("\nInvalid address/ Address not supported \n");
        return -1;
    }

    // 连接到服务器
    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        printf("\nConnection Failed \n");
        return -1;
    }

    // 向服务器发送消息
    send(sock, hello, strlen(hello), 0);
    printf("Hello message sent\n");

    // 读取服务器发来的消息
    valread = read(sock, buffer, MAX_BUFFER_SIZE);
    printf("Message from server: %s\n", buffer);

    return 0;
}

编译并运行服务器端代码：

gcc server.c -o server
./server

编译并运行客户端代码：

gcc client.c -o client
./client

在客户端终端可以看到以下输出：

Hello message sent
Message from server: Hello from server