基于TCP的网络编程

服务器端程序：

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

#pragma comment( lib, "Wsock32.lib" )            //加入lib库

void main()
{
    //加载套接字库
    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 ;
    }

    //创建用户监听的套接字
    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 );

    //绑定套接字
    bind( sockSrv,(SOCKADDR*)&addrSrv,sizeof( SOCKADDR ) );
    //将套接字设为监听模式，准备接受客户请求
    listen( sockSrv,5 );

    SOCKADDR_IN addrClient;
    int len = sizeof( SOCKADDR );

    while ( 1 ){
        //等待客户请求到来
        SOCKET sockConn = accept( sockSrv,(SOCKADDR*)&addrClient,&len );
        char sendBuf[100];
        sprintf( sendBuf,"Welcome %s to http://www.sunxin.org",inet_ntoa( addrClient.sin_addr ) );
        //发送数据
        send( sockConn,sendBuf,strlen( sendBuf )+1,0 );
        char recvBuf[100];
        //接受数据
        recv( sockConn,recvBuf,100,0 );
        //打印接受的数据
        printf( "%s\n",recvBuf );
        //关闭套接字
        closesocket( sockConn );
    }
}

客户端程序：

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

#pragma comment( lib, "Wsock32.lib" )            //加入lib库

void main()
{
    //加载套接字库
    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 ;
    }

    //创建套接字
    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 );

    //向服务器发出连接请求
    connect( sockClient,(SOCKADDR*)&addrSrv,sizeof( SOCKADDR ) );

    //接收数据
    char recvBuf[100];
    recv( sockClient,recvBuf,100,0 );
    printf( "%s\n",recvBuf );

    //发送数据
    send( sockClient,"This is lisi",strlen( "This is lisi" )+1,0 );

    //关闭套接字
    closesocket( sockClient );
    WSACleanup();
}

先启动服务器端程序，在运行客户端程序。连接之后接收服务器发来的欢迎信息，在发给位于本机6000端口的服务器程序一条信息“This is lisi”。