c++ socket编程入门 c++网络通信代码实例

核心是使用socket API实现TCP通信，服务端依次创建套接字、绑定、监听、接受连接并收发数据，客户端则连接后发送消息并接收响应，需注意跨平台差异与错误处理。

想快速上手 C++ Socket 编程？其实核心就是使用操作系统提供的 socket API，通过创建套接字、绑定地址、监听连接（服务端）或发起连接（客户端），实现网络通信。下面以 TCP 为例，给出一个简单但完整的 C++ 网络通信实例，包含服务端和客户端代码，适用于 Linux 和 Windows（稍作调整）。

服务端代码：接收客户端消息并回传

服务端负责监听指定端口，等待客户端连接，收到数据后原样返回。

Linux / macOS 版本（g++ 编译）：

#include 
#include 
#include 
#include 
#include 

int main() {
    int server_fd, new_socket;
    struct sockaddr_in address;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};
    
    // 创建套接字
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
        perror("socket failed");
        exit(EXIT_FAILURE);
    }

    // 配置地址结构
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(8080);

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

    // 监听
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    std::cout << "Server listening on port 8080...\n";

    // 接受连接
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0) {
        perror("accept");
        exit(EXIT_FAILURE);
    }

    // 读取客户端消息
    read(new_socket, buffer, 1024);
    std::cout << "Client: " << buffer << "\n";

    // 回传消息
    const char *response = "Hello from server";
    send(new_socket, response, strlen(response), 0);
    std::cout << "Response sent\n";

    close(new_socket);
    close(server_fd);
    return 0;
}

Windows 版本需包含 Winsock：

#include 
#include 
#include 
#pragma comment(lib, "ws2_32.lib")

int main() {
    WSADATA wsa;
    SOCKET server_fd, new_socket;
    struct sockaddr_in address;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};

    if (WSAStartup(MAKEWORD(2,2), &wsa) != 0) {
        std::cerr << "WSAStartup failed\n";
        return 1;
    }

    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
        std::cerr << "Socket creation error\n";
        WSACleanup();
        return 1;
    }

    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(8080);

    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) == SOCKET_ERROR) {
        std::cerr << "Bind failed\n";
        closesocket(server_fd);
        WSACleanup();
        return 1;
    }

    if (listen(server_fd, 3) == SOCKET_ERROR) {
        std::cerr << "Listen failed\n";
        closesocket(server_fd);
        WSACleanup();
        return 1;
    }
    std::cout << "Server listening on port 8080...\n";

    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, &addrlen)) == INVALID_SOCKET) {
        std::cerr << "Accept failed\n";
        closesocket(server_fd);
        WSACleanup();
        return 1;
    }

    recv(new_socket, buffer, 1024, 0);
    std::cout << "Client: " << buffer << "\n";

    const char *response = "Hello from server";
    send(new_socket, response, strlen(response), 0);
    std::cout << "Response sent\n";

    closesocket(new_socket);
    closesocket(server_fd);
    WSACleanup();
    return 0;
}

客户端代码：连接服务端并发送消息

客户端主动连接服务端，发送一条消息，并接收响应。

Linux / macOS 客户端：

#include 
#include 
#include 
#include 
#include 

int main() {
    int sock = 0;
    struct sockaddr_in serv_addr;
    char *hello = "Hello from client";
    char buffer[1024] = {0};

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        std::cerr << "Socket creation error\n";
        return -1;
    }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(8080);

    // 将 IP 地址从文本转换为二进制
    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
        std::cerr << "Invalid address / Address not supported\n";
        return -1;
    }

    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
        std::cerr << "Connection Failed\n";
        return -1;
    }

    send(sock, hello, strlen(hello), 0);
    std::cout << "Message sent to server\n";

    read(sock, buffer, 1024);
    std::cout << "Server response: " << buffer << "\n";

    close(sock);
    return 0;
}

Windows 客户端： 同样需要初始化 Winsock，其余逻辑一致，把 socket、connect、send、recv 替换为 Windows 对应函数即可。

编译与运行（Linux 示例）

保存服务端代码为 server.cpp，客户端为 client.cpp。

g++ server.cpp -o server
g++ client.cpp -o client

终端1运行服务端：
./server
终端2运行客户端：
./client

观察输出，确认通信成功。

关键点说明

• AF_INET 表示 IPv4 协议族，SOCK_STREAM 表示 TCP 流式套接字。
• 服务端依次调用 socket → bind → listen → accept。
• 客户端调用 socket → connect → send/recv。
• 注意错误检查，真实项目中不能忽略返回值。
• 跨平台开发建议封装接口，或使用 Boost.Asio 等库简化操作。

基本上就这些，不复杂但容易忽略细节。