socket通信C++示例

下面是一个简单的使用Socket进行通信的C++示例：

#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

using namespace std;

const int PORT = 8080;

int main() {
    int server_fd, new_socket;
    struct sockaddr_in address;
    int opt = 1;
    int addrlen = sizeof(address);
    char buffer[1024] = {0};
    const 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");
        exit(EXIT_FAILURE);
    }
    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(PORT);
       
    // 绑定socket到指定端口
    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address))<0) {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }
       
    // 监听socket
    if (listen(server_fd, 3) < 0) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
       
    // 接受客户端连接请求
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0) {
        perror("accept");
        exit(EXIT_FAILURE);
    }
       
    // 从客户端接收消息
    int valread;
    if ((valread = read(new_socket, buffer, 1024)) == 0) {
        cout << "Client disconnected" << endl;
    } else {
        cout << "Received message: " << buffer << endl;
    }
       
    // 向客户端发送消息
    send(new_socket, hello, strlen(hello), 0);
    cout << "Hello message sent" << endl;
    return 0;
}

这个示例创建了一个TCP服务器，监听8080端口。当有客户端连接时，服务器将从客户端接收消息，打印消息内容，并向客户端发送“Hello from server”消息。