C++ 함수는 네트워크 프로그래밍에서 데이터 전송을 어떻게 구현합니까?

int recv(int sockfd, void *buf, size_t len, int flags);

int send(int sockfd, const void *buf, size_t len, int flags);

#include <iostream>
#include <stdlib.h>
#include <sys/socket.h> // 套接字支持
#include <netinet/in.h> // 互联网地址结构支持

using namespace std;

int main() {
  // 创建套接字
  int server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
  if (server_sockfd < 0) {
    cerr << "错误：无法创建套接字！" << endl;
    return -1;
  }

  // 设置服务器地址信息
  sockaddr_in server_addr;
  server_addr.sin_family = AF_INET;
  server_addr.sin_port = htons(8080); // 将端口号转换为网络字节序
  server_addr.sin_addr.s_addr = INADDR_ANY; // 接受任何 IP 地址的连接

  // 绑定套接字到服务器地址
  if (bind(server_sockfd, (struct sockaddr *) &server_addr, sizeof(server_addr)) < 0) {
    cerr << "错误：绑定套接字失败！" << endl;
    return -1;
  }

  // 监听连接
  if (listen(server_sockfd, 5) < 0) {
    cerr << "错误：监听连接失败！" << endl;
    return -1;
  }

  while (true) {
    // 接受连接
    sockaddr_in client_addr;
    socklen_t client_addr_len = sizeof(client_addr);
    int client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_addr, &client_addr_len);
    if (client_sockfd < 0) {
      cerr << "错误：接受连接失败！" << endl;
      continue;
    }

    // 接收和发送数据
    char buffer[1024]; // 用于存储数据的缓冲区
    int n;
    while ((n = recv(client_sockfd, buffer, sizeof(buffer), 0)) > 0) {
      // 发送回客户端
      int m = send(client_sockfd, buffer, n, 0);
      if (m < 0) {
        cerr << "错误：发送数据失败！" << endl;
        break;
      }
    }

    // 关闭连接
    close(client_sockfd);
  }

  // 关闭套接字
  close(server_sockfd);

  return 0;
}