WinSock 2: client that uses WinSock to implement socket communication.

Compiling environment: VC ++ 6.0

/*
* File: client. cpp
*
*/

# Include <winsock2.h>
# Include <stdio. h>
# Include <stdlib. h>

# Define default_port 5150.
# Define default_buffer 4096.
# Define default_message "login"
# Define default_count 20
Int iport = default_port;

Char szserver [128];
Char szmessage [1024];
DWORD dwcount = default_count;
Bool bsendonly = false;
// Function: Usage
// Description:
// Print usage information and exit
Void usage ()
{
Printf ("Usage: Client [-P: X] [-I: IP] [-N: X] [-O]/n ");
Printf ("-P: X remote port to send to/N ");
Printf ("-I: Str server's address or host name/N ");
Printf ("-N: X number of times to send message/N ");
Printf ("-o send messages only; don't recevie/N ");
Printf ("Camel 2004-8-29 ");
Exitprocess (1 );
}

// Function:
Void validateargs (INT argc, char ** argv)
{
Int I;
For (I = 1; I <argc; I ++)
{
If (argv [I] [0] = '-') | (argv [1] [0] = '/'))
{
Switch (tolower (argv [I] [1])
{
Case 'p ':
Iport = atoi (& argv [I] [3]);
Break;
Case 'I ':

If (strlen (argv [I])> 3)
Strcpy (szserver, & argv [I] [3]);
Break;
Case 'N ':
If (strlen (argv [I])> 3)
Dwcount = atoi (& argv [I] [3]);
Case 'O ':
Bsendonly = true;
Break;
Default:
Usage ();
Break;
}
}
}

}

Int main (INT argc, char ** argv)
{
Wsadata WSD;
Socket sclient;
Char szbuffer [default_buffer];
Int ret, I;

Struct sockaddr_in server;
Struct hostent * Host = NULL;
Printf ("===== client =====/N ");
Validateargs (argc, argv );
If (wsastartup (makeword (2, 2), & WSD )! = 0)
{
Printf ("failed to load Winsock! /N ");
Return 1;
}

Strcpy (szmessage, default_message );

//
// Create the socket, and attempt to connect to the server
//
Sclient = socket (af_inet, sock_stream, ipproto_ip );
If (sclient = socket_error)
{
Printf ("socket () failed: % d/N", wsagetlasterror ());
Return 1;
}
// Select the local interface, and bind to it
Server. sin_family = af_inet;
Server. sin_port = htons (iport );
Server. sin_addr.s_addr = inet_addr (szserver );

//
// If the supplied server address wasn't in the form
// "AAA. BBB. ccc. DDD" it's a host name, so try to resolver it
//
If (server. sin_addr.s_addr = inaddr_none)
{
Host = gethostbyname (szserver );
If (host = NULL)
Printf ("unable to resolve server: % s/n", szserver );
Return 1;
}
Printf ("Debug: copymemory ");
// Copymemory (& server. sin_addr, host-> h_addr_list [0], host-> h_length );
Printf ("Debug: copymemory over ");
 
If (connect (sclient, (struct sockaddr *) & server, sizeof (server) = socket_error)
{
Printf ("Connect () failed: % d] n", wsagetlasterror ());
Return 1;
}
//
// Send and receive data
//
For (I = 0; I <dwcount; I ++)
{
Ret = Send (sclient, szmessage, strlen (szmessage), 0 );
If (ret = 0)
Break;
Else if (ret = socket_error)
{
Printf ("Send () failed: % d/N", wsagetlasterror );
Break;
}
Printf ("Send % d Bytes/N", RET );
If (! Bsendonly)
{
Ret = Recv (sclient, szbuffer, default_buffer, 0 );
If (ret = 0)
Break;
Else if (ret = socket_error)
{
Printf ("Recv () failed: % d/N", wsagetlasterror ());
Break;
}
Szbuffer [RET] = '/0 ';
Printf ("Recv [% d bytes]: '% s'/N", RET, szbuffer );
}
}
Closesocket (sclient );
Wsacleanup ();
Return 0;
}