C / C++ / MFC

void CMyControl::OnDraw(CDC* pdc, const CRect& rcBounds, const CRect& rcInvalid)
{
        // m_ctrlDictSel is my child control (could be two of them)
	if (m_ctrlDictSel.GetSafeHwnd())
	{
                // Here we resize the child controls if the ActiveX control
                // size has changed, otherwise, just redraw the child wnds.
                //
		if (m_tRect != rcBounds)
		{
			m_ctrlDictSel.MoveWindow(rcBounds, TRUE);
			m_tRect = rcBounds;
		}
		else
		{
			m_ctrlDictSel.Invalidate(TRUE);
		}
	}
	else
	{
                // Design mode, draw a crossed box.
                //
		pdc->FillRect(rcBounds, CBrush::FromHandle((HBRUSH)GetStockObject(WHITE_BRUSH)));
		pdc->Rectangle(rcBounds);
		pdc->MoveTo(rcBounds.left, rcBounds.top);
		pdc->LineTo(rcBounds.right, rcBounds.bottom);
		pdc->MoveTo(rcBounds.right, rcBounds.top);
		pdc->LineTo(rcBounds.left, rcBounds.bottom);
	}
}

int CMyCtrl::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
	if (COleControl::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	// TODO: Add your specialized creation code here

	// Initialise the tree controls
	DWORD	dwStyle = WS_CHILD | WS_VISIBLE | 
		TVS_HASLINES | TVS_DISABLEDRAGDROP;
	UINT	nFlags	= SWP_NOMOVE | SWP_NOSIZE;
	BOOL bCreate = m_tree.Create(dwStyle, CRect(7, 7, 70, 75), this, IDC_TREE);
	if(TRUE == bCreate)
	{
		m_tree.SetWindowPos(&wndTop, 0, 0, 0, 0, nFlags);
	}

	return 0;
}

void CMyCtrl::OnSize(UINT nType, int cx, int cy) 
{
	COleControl::OnSize(nType, cx, cy);
	
	m_tree.SetWindowPos(&wndTop, 7, 7, 70, 75, 0);
}

class Pool<t>
{
// Define Pool class methods.

};

Pool<car> MyCars;
Pool<truck> MyTrucks; 

Good Luck,

Bill

class Pool<T>
{
// Define common methods

void Maintain();

// Expose class methods
T.Start();

};

To use it:

Pool<Cars> MyCars;
Pool<Trucks> MyTrucks;
MyTrucks.Start();

MyTrucks.Maintain();