記得要 link Ws2_32.lib, 如果用的是 Visual C++, 選 Project, Settings...

  選 Link, 在 Object/library modules: 加進 Ws2_32.lib, 選 OK 即可~

--

#include <Winsock2.h>
#include <iostream>
#include <stdio.h>

using namespace std;

int main()
{
   SOCKET server_sockfd,client_sockfd;
   int server_len, client_len;
   struct sockaddr_in server_address;
   struct sockaddr_in client_address;

   {
            WORD wVersionRequested;
                WSADATA wsaData;
                int err;

                wVersionRequested = MAKEWORD( 2, 2 );

                err = WSAStartup( wVersionRequested, &wsaData );
                if ( err != 0 ) {
                        return 1;
                }

                if ( LOBYTE( wsaData.wVersion ) != 2 ||
                                HIBYTE( wsaData.wVersion ) != 2 ) {
                        WSACleanup( );
                }
   }

   server_sockfd=socket(AF_INET,SOCK_STREAM,0);
   server_address.sin_family=AF_INET;
   server_address.sin_addr.s_addr=inet_addr("140.112.30.125");
   cout << server_address.sin_addr.s_addr << '\n';
   server_address.sin_port=1234;//htons(1234);
   server_len=sizeof(server_address);
   if(bind(server_sockfd,(struct sockaddr *)&server_address,server_len)!=0)
{
           cout << WSAGetLastError() << '\n';
           printf("Error bind\n");
           exit(0);
   }
   listen(server_sockfd,5);
   {
   char ch[10] ="default";
   printf("server waiting....\n");
   client_len = sizeof(client_address);
   client_sockfd=accept( server_sockfd,
         (struct sockaddr * ) & client_address, &client_len);
   recv(client_sockfd,ch,10,1);
   printf("%s\n",ch);
   closesocket(client_sockfd);
  }
   return 0;
}