本程序仅仅是为了演示基于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。