#include <sys\types.h>
#include <sys\socket.h>
#include <netinet\in.h>
#include <iostream.h>
#include <string.h>

// this program expects the server address as a parameter

void main(int argc, char *argv[])
{
  int s,           // the socket handle
      rc;          // return code
  char szBuf[256];       // data buffer
  struct sockaddr_in server; // server address

  if (argc != 2) {
    cerr << "Error! Incorrect number of arguments." << endl;
    return;
    }

  s = socket(AF_INET, SOCK_STREAM, 0);
  if (s < 0) {
    cerr << "Error! Cannot create socket." << endl;
    return;
    }
  bzero(&server, sizeof(struct sockaddr_in);
  server.sin_family = AF_INET;
  server.sin_port = htons(7777);
  server.sin_addr = inet_addr(argv[1]);  // use command line address

  rc = connect(s, (struct sockaddr *) &server, sizeof(struct sockaddr_in));
  if (rc < 0) {
    cerr << "Error! Connect failed." << endl;
    return;
    }

  // do some processing of data between client and server
  strcpy(szBuf, "HELLO\r\n");
  rc = send(s, szBuf, strlen(szBuf), 0);
  if (rc < 0) {
    cerr << "Error! Send failed." << endl;
    return;
    }

  rc = RecvLine(s, szBuf, 256);
  if (rc < 0) {
    cerr << "Error! RecvLine failed." << endl;
    return;
    }

  if (strcmp(szBuf, "OK") != 0) {
    cerr << "Error! Unknown reply from server." << endl;
    return;
    }

  strcpy(szBuf, "GOODBYE\r\n");
  rc = send(s, szBuf, strlen(szBuf), 0);
  if (rc < 0) {
    cerr << "Error! Send failed." << endl;
    return;
    }

  rc = RecvLine(s, szBuf, 256);
  if (rc < 0) {
    cerr << "Error! RecvLine failed." << endl;
    return;
    }

  if (strcmp(szBuf, "OK") != 0) {
    cerr << "Error! Unknown reply from server." << endl;
    return;
    }

  close(s);
}

// ----------------------------------------------------------------
// Receive a command line terminated by a telnet eol sequence

int RecvLine(int iSocket, char *szBuf, int iLen)
{
  int iBytesRead,
      iIdx,
      bNotDone;

  iBytesRead = recv(iSocket, &szBuf[0], 1, 0);
  iIdx = 1;
  bNotDone = TRUE;

  while (bNotDone == TRUE) {
    iBytesRead = recv(iSocket, &szBuf[iIdx], 1, 0);
    if (iBytesRead < 0) {
      return ( -1 );  // error receiving
      }

    iIdx++;
    if ( (szBuf[iIdx - 2] == '\r') &&
         (szBuf[iIdx – 1] == '\n')  ) {
      bNotDone = FALSE;  // got telnet eol
      }
    if (iIdx == iLen) {
      return ( -1 ); // error, buffer too small
      }
    }

   szBuf[iIdx - 2] = NULL;  // append null termination
   return ( TRUE );
}