一、服务端程序

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

void main()
{
WORD wVersionRequested;
WSADATA wsaData;
int err;
wVersionRequested = MAKEWORD( 1, 1 );
err = WSAStartup( wVersionRequested, &wsaData );
if ( err != 0 ) {
  return;
}

if ( LOBYTE( wsaData.wVersion ) != 1 || HIBYTE( wsaData.wVersion ) != 1 ) {
  WSACleanup( );
  return;
}

SOCKET sockSrv=socket(AF_INET,SOCK_STREAM,0);
SOCKADDR_IN addrSrv;
addrSrv.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
addrSrv.sin_family=AF_INET;
addrSrv.sin_port=htons(6000);

bind(sockSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));

listen(sockSrv,5);

SOCKADDR_IN addrClient;

int len=sizeof(SOCKADDR);

while(1)
{
  SOCKET sockConn=accept(sockSrv,(SOCKADDR*)&addrClient,&len);

  char sendBuf[50];
  sprintf(sendBuf,"Welcome %s to here!",inet_ntoa(addrClient.sin_addr));

  send(sockConn,sendBuf,strlen(sendBuf)+1,0);

  char recvBuf[50];
  recv(sockConn,recvBuf,50,0);

  printf("%s\n",recvBuf);

  closesocket(sockConn);
}
}

二、客户端程序

#include <stdio.h>
#include <Winsock2.h>
​​​​​​​
void main()
{
 WORD wVersionRequested;
 WSADATA wsaData;
 int err;
 
 wVersionRequested = MAKEWORD( 1, 1 );
 
 err = WSAStartup( wVersionRequested, &wsaData );
 if ( err != 0 ) {
  return;
 }
 
 if ( LOBYTE( wsaData.wVersion ) != 1 || HIBYTE( wsaData.wVersion ) != 1 ) {
  WSACleanup( );
  return;
 }

 SOCKET sockClient=socket(AF_INET,SOCK_STREAM,0);
 
 SOCKADDR_IN addrSrv;
 addrSrv.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");
 addrSrv.sin_family=AF_INET;
 addrSrv.sin_port=htons(6000); connect(sockClient,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR)); send(sockClient,"hello",strlen("hello")+1,0);
 char recvBuf[50]; recv(sockClient,recvBuf,50,0);
 printf("%s\n",recvBuf); 
 closesocket(sockClient);
 WSACleanup();
}