用C++创建一个简单的UDP服务端

#include <WinSock2.h>
#include <Windows.h>
#include <iostream>
#pragma comment(lib,"ws2_32.lib")
using namespace std;
int main() 
{
  WSADATA d;
  WORD w = MAKEWORD(2, 0);
  WSAStartup(w, &d);
  SOCKET s = socket(AF_INET, SOCK_DGRAM, 0);

  sockaddr_in addr;
  addr.sin_family = AF_INET;
  addr.sin_addr.S_un.S_addr = INADDR_ANY;
  addr.sin_port = htons(9999);

  bind(s, (sockaddr*)&addr, sizeof(addr));

  char buf[512] = {0};

  sockaddr_in addrClient = {};
  int sockLen = sizeof(sockaddr_in);

  char bufsend[] = "Hello,UDP Client!";


  cout << "UDP SERVER IS START AND BIND TO 9999" << endl;
  while (true) {
    
    sendto(s, bufsend, strlen(bufsend), 0, (sockaddr*)&addrClient, sockLen);

    int recvLen = recvfrom(s, buf, 512, 0, (sockaddr*)&addrClient, &sockLen);
    if (recvLen > 0) {
      cout << buf << endl;
    }

  
  }

  closesocket(s);
  WSACleanup();
  return 0;
}