服務端:
#include <stdlib.h>
#include <stdio.h>
#include <WINSOCK2.H>
#include <WS2TCPIP.H>
#include <windows.h>

//////////////////////////////////////////////////////////////////////////

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

//////////////////////////////////////////////////////////////////////////

int  main()
{
 WSADATA wsaData;
 SOCKET listenSocket = INVALID_SOCKET;
 SOCKET clientSocket = INVALID_SOCKET;
 char recvBuf[DEFAULT_BUFLEN];
 int iResult,iSendResult;
 int recvBuflen = DEFAULT_BUFLEN;

 iResult = WSAStartup(MAKEWORD(2,0),&wsaData);
 if(iResult)
 {
  printf("WSASTATUP failed!\n");
  return 1;
 }
 
 listenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 if(listenSocket == INVALID_SOCKET)
 {
  printf("socket failed:%ld\n", WSAGetLastError());
  WSACleanup();
  return 1;
 }
 
 
 sockaddr_in saServer;
 saServer.sin_family = AF_INET;
 saServer.sin_addr.s_addr = inet_addr("127.0.0.1");
 saServer.sin_port = htons(5150);

 iResult = bind(listenSocket,(sockaddr *)&saServer, sizeof(saServer));
 if(iResult == SOCKET_ERROR)
 {
  printf("bind failed!");
  closesocket(listenSocket);
  WSACleanup();
  return 1;
 }
 iResult = listen(listenSocket, SOMAXCONN);
 if(iResult == SOCKET_ERROR)
 {
  printf("LISTEN failed!");
  closesocket(listenSocket);
  WSACleanup();
  return 1;
 }
 printf("Wait client connect");
 clientSocket = accept(listenSocket, NULL, NULL);
 if(clientSocket == INVALID_SOCKET)
 {
  printf("accept failed!");
  closesocket(listenSocket);
  WSACleanup();
  return 1;
 }
 closesocket(listenSocket);
 printf("Now wait the data arrive...\n");
 do
 {
  iResult = recv(clientSocket, recvBuf, recvBuflen, 0);
  if(iResult > 0)
  {
   printf("Bytes received:%d\n",iResult);
   iSendResult = send(clientSocket, recvBuf, iResult, 0);
   if(iSendResult == SOCKET_ERROR)
   {
    printf("send failed");
    closesocket(clientSocket);
    WSACleanup();
    return 1;
   }
   else if (iResult == 0)
   {
    printf("Connect closed!");
   }
   else
   {
    printf("recv failed");
    closesocket(clientSocket);
    WSACleanup();
    return 1;
   }
  }
 } while(iResult > 0);

 iResult = shutdown(clientSocket, SD_SEND);
 if(iResult == SOCKET_ERROR)
 {
  printf("shut dowm failed!");
  closesocket(clientSocket);
  WSACleanup();
  return 1;
 }
 closesocket(clientSocket);
 WSACleanup();
 getchar();
 return 0;
}

//客戶端
#include <stdlib.h>
#include <stdio.h>
#include <WINSOCK2.H>
#include <WS2TCPIP.H>
#include <windows.h>

//////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "27015"

//////////////////////////////////////////////////////////////////////////

int main()
{
 WSADATA wsaData;
 SOCKET connectSocket = INVALID_SOCKET;
 char *sendBuf = "This is a test";
 char recvBuf[DEFAULT_BUFLEN];
 int iResult;
 int recvBufLen = DEFAULT_BUFLEN;
//  if(argc != 2)
//  {
//   printf("useage:%s server -name\n",argv[0]);
//   return 1;
//  }
 iResult = WSAStartup(MAKEWORD(2,0),&wsaData);
 if(iResult)
 {
  printf("WSASTATUP FAILED.");
  return 1;
 }
 sockaddr_in addr;
 addr.sin_family = AF_INET;
 addr.sin_port = htons(5150);
 addr.sin_addr.s_addr = inet_addr("127.0.0.1");
 connectSocket =  socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 if(connectSocket == INVALID_SOCKET)
 {
  printf("Error at socket!");
  WSACleanup();
  return 1;
 }
 iResult = connect(connectSocket, (sockaddr *)&addr, sizeof(addr));
 if(iResult == SOCKET_ERROR)
 {
  printf("Connect failed!");
  WSACleanup();
  return 1;
 }

 iResult = send(connectSocket, sendBuf, (int)strlen(sendBuf), 0);
 if(iResult == SOCKET_ERROR)
 {
  printf("Send failed");
  closesocket(connectSocket);
  WSACleanup();
  return 1;
 }
 printf("Bytes send.");
 iResult = shutdown(connectSocket, SD_SEND);
 if(iResult == SOCKET_ERROR)
 {
  printf("shut down failed");
  closesocket(connectSocket);
  WSACleanup();
  return 1;
 }
 do
 {
  iResult = recv(connectSocket, recvBuf, recvBufLen, 0);
  if(iResult > 0)
  {
   printf("Bytes received:%d\n",iResult);
  }
  else if(iResult == 0)
  {
   printf("connect closed");
  }
  else
  {
   printf("Recv failed");
  }
 } while(iResult > 0);
 closesocket(connectSocket);
 WSACleanup();
 return 0;
}
注意要加入鏈接庫WS2_32.lib