本程序仅仅是为了演示基于TCP协议,TCP协议的网络通信程序的写法，采用阻塞模式，代码简单：

服务器端代码：

#include "Winsock2.h"
#include "stdio.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[100];

sprintf(sendBuf,"Welcom %s to http://blog.hulin0229.com", inet_ntoa(addrClient.sin_addr));
send(sockConn,sendBuf,strlen(sendBuf)+1,0);

char recvBuf[100];
recv(sockConn,recvBuf,strlen(recvBuf),0);
printf("%s\n",recvBuf);
closesocket(sockConn);
}
}

『注意』本程序使用了动态连接库文件Ws2_32.lib，需要在工程属性里添加对Ws2_32.lib的连接。本程序用VC2005编译，添加方法是：在project\Configuration properties\Linker\Input下的Additional Dependencies 项里写如Ws2_32.lib

客户端代码：

#include "Winsock2.h"
#include "stdio.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"); //127.0.0.1是

一个回路地址。
addrSrv.sin_family=AF_INET;
addrSrv.sin_port=htons(6000);

connect(sockClient,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));

char recvBuf[100];
recv(sockClient,recvBuf,strlen(recvBuf),0);
printf("%s\n",recvBuf);
send(sockClient,"我是胡林",strlen("我是胡林")+1,0);
closesocket(sockClient);
WSACleanup();
}

同服务器端一样，客户端程序也使用了Ws2_32.lib动态连接库，需要在工程属性里添加对Ws2_32.lib的连接。