C / C++ / MFC

class Tree{
public:
   virtual string print(){return "Problem";}
}

class Leaf: public Tree{
private:
   string name;
public:
   Leaf(string s){
      name = s;
   }
   
   string print(){
      return name;
   }
}

class SubTree: public Tree{
private:
   Tree* left;
   Tree* right;
public:
   SubTree(string s){
      for(int x=0; x< s.size(); x++){
         if(string.at(x) == 'V'){
            if(string.at(0) == '(')
               left = new SubTree(s.substr(1,x-1));
            else
               left = new Leaf(s.substr(0,x));
            if(string.at(x+1) == '(')
               right = new SubTree(s.substr(x+2,s.size()-1));
            else
               right = new Leaf(s.substr(x+1,s.size()));
         }
      }
   }

   string print(){
      return "(" + left->print() + "V" + right->print() + ")";
   }
}

UINT ListeningThread(LPVOID lpvoid)
{
    CMultycast_serverDlg *dlg = (CMultycast_serverDlg *)lpvoid;
    FD_SET SocketSet;               // set of socket descriptors for select()
    int port;                       // looping veriable for ports
    struct sockaddr_in echoClntAddr;// client address
    SOCKET clntSock;                // socket discriptor for client
    unsigned int clntLen;           // length of client address data structure
    int SelectResult = 0;

    dlg->SelectFlag = false;
    dlg->ExitFlag = false;
    while(!dlg->ExitFlag)
    {
        FD_ZERO(&SocketSet);
        for(port = 0 ; port < dlg->NumberOfPorts ; port++)
   	FD_SET((unsigned int)dlg->SocketsArray[port] , &SocketSet);
	SelectResult = select(dlg->MaxDescriptor + 1 , &SocketSet , NULL , 
                              NULL , &(dlg->selTimeout));
	if(SelectResult == 0)
	  continue;//AfxMessageBox("Error :  No echo requests for the time 
                                   you specified....server still listenning");
	else if(SelectResult == SOCKET_ERROR)
	{
	    AfxMessageBox("Error :  select() has failed ");
	    return 0 ;
	}
	else
	{
	    //dlg->SelectFlag = true;
	    for(port = 0 ; port < dlg->NumberOfPorts ; port++)
	    {
	        if(FD_ISSET(dlg->SocketsArray[port] , &SocketSet))
		{
		    clntLen = sizeof(echoClntAddr);//set the size of the in-  out parameter
		    //if(!dlg->SelectFlag)
		    clntSock=accept(dlg->SocketsArray[port],(struct sockaddr*)&echoClntAddr,(int *)&clntLen);
		    //dlg->SelectFlag = true;
		    if(clntSock != INVALID_SOCKET) //wait for a client to connect
		    {
		 	dlg->HandleClient(clntSock);//clntSock is connected to a client
	 		dlg->m_RecievedDataListBox.AddString(dlg->RecievedString);
			//WSACleanup();
	              }
                  }  
            } 
	}
   }
   for(port = 0 ; port < dlg->NumberOfPorts ; port++)
      closesocket(dlg->SocketsArray[port]);
   return 1;
}