integer queue in BCB

The h file

//---------------------------------------------------------------------------
#ifndef MyQueueH
#define MyQueueH
//---------------------------------------------------------------------------
#include 
#include 
#include 
#include 
//---------------------------------------------------------------------------
class PACKAGE TMyIntNode : public TObject
{
private:
 int fdata;
 TMyIntNode  *fnext;
 TMyIntNode  *fprev;
protected:
public:
 __fastcall TMyIntNode(int u);
 __fastcall TMyIntNode();
 __fastcall ~TMyIntNode();
__published:
 __property int data={read=fdata,write=fdata};
 __property TMyIntNode *next={read=fnext,write=fnext};
 __property TMyIntNode *prev={read=fprev,write=fprev};

};
//
// TMyIntQueue q;
//
// q= new TMyIntQueue();
// q->queue(5);
//
// if q->count>0 { i = q->unqueue(); }
//
class PACKAGE TMyIntQueue: public TObject
{
 private:
  int fcount;
  TMyIntNode *fhead;
  TMyIntNode *ftail;
 protected:
 public:
 __fastcall TMyIntQueue();
 __fastcall ~TMyIntQueue();
 __fastcall queue(int z);
 int __fastcall unqueue();

__published:
 __property int count={read=fcount,write=fcount};

};

//---------------------------------------------------------------------------
#endif
 

The cpp file

//---------------------------------------------------------------------------
#include 
#pragma hdrstop

#include "MyQueue.h"
#pragma package(smart_init)
//---------------------------------------------------------------------------
// ValidCtrCheck is used to assure that the components created do not have
// any pure virtual functions.
//
//static inline void ValidCtrCheck(TMyIntNode *)
//{
//        new TMyIntNode(NULL);
//}
//---------------------------------------------------------------------------
__fastcall TMyIntNode::TMyIntNode(int u)
        : TObject()
{
 fdata = u;
 fnext=NULL;
 fprev=NULL;
}

__fastcall TMyIntNode::TMyIntNode()
{
 fdata = 0;
 fnext=NULL;
 fprev=NULL;
}

__fastcall TMyIntNode::~TMyIntNode()
{
 //
}

//.........................................................................
__fastcall TMyIntQueue::TMyIntQueue()
{
 fhead = NULL;
 ftail = NULL;
 fcount =0;
}
__fastcall TMyIntQueue::~TMyIntQueue()
{
 int h;
 while (fhead != NULL)
 {
  h= unqueue();
 }
}
__fastcall TMyIntQueue::queue(int z)
{
 TMyIntNode *u;

 u=new TMyIntNode(z);
 if (fhead==NULL)
  {
   fhead=u;
   ftail=u;
   fcount++;
  }
 else {
  u->next=fhead;
  fhead->prev=u;
  fhead=u;
  fcount++;
  }
}
int __fastcall TMyIntQueue::unqueue()
{
 TMyIntNode *u;
 int i;
 if (ftail !=NULL) {
  u=ftail;
  ftail=u->prev;
  if (ftail==NULL){fhead=NULL;}
  fcount--;
  i=u->data;
  u->TMyIntNode::~TMyIntNode();
  return i;
 }
}


//---------------------------------------------------------------------------
//namespace Myqueue
//{
//        void __fastcall PACKAGE Register()
//        {
//                 TComponentClass classes[1] = {__classid(TMyIntNode)};
//                 RegisterComponents("Samples", classes, 0);
//        }
//}
//---------------------------------------------------------------------------
 

a test environment

place 3 buttons : init_queue, queue_in, queue_out onto a form.
place a spinedit qiv
place 2 labels qcount, outnumber

the init_queue click :

void __fastcall TForm1::init_queueClick(TObject *Sender)
{
 q = new TMyIntQueue();        
}

the queue_in click :

void __fastcall TForm1::queue_inClick(TObject *Sender)
{
 int t;
 t = qiv->Value;
 q->queue(t);
 qcount->Caption=IntToStr(q->count);
}

the queue_out click :

void __fastcall TForm1::queue_outClick(TObject *Sender)
{
 int t;
 if (q->count == 0) exit;
 t = q->unqueue();
 outnumber->Caption=IntToStr(t);
 qcount->Caption=IntToStr(q->count);
}