C / C++ / MFC

int x=1, y=5; 
x^=y^=x^=y; // whats the content of x and y now?
<a href="http://www.codeproject.com/tips/StupidXORTrick.asp" target="_blank">ClickHereForHelp();</a>

template <class T>
class Ptr
{
public:
	Ptr(T* pp = NULL) { p = pp; }



	template <class T2>
	void Assign(T2 *pp)
	{
		p = pp;
	}

private:
	T *p;
};

Ptr<CWnd> pw;
CDialog d;
pw.Assign(&d); // compiles OK
CString s;
pw.Assign(&s); // compiler error - can't convert from CString * to CWnd

void CNewView::OnDraw(CDC* pDC)
{
//	CDocument* pDoc = GetDocument(); // no document for the beginning; you can add it lately
	// TODO: add draw code here
}

BOOL CMainFrame::OnCreateClient(LPCREATESTRUCT lpcs, CCreateContext* pContext) 
{
  if (!m_split.CreateStatic(GetParentOwner(), 1, 2))
    AfxMessageBox("Failure on split creation!");
  m_split.CreateView(0, 0, RUNTIME_CLASS(CNewView), CSize(0, 0), pContext);
  m_split.CreateView(0, 1, RUNTIME_CLASS(CNewView), CSize(0, 0), pContext);
  PostMessage(WM_SIZE);

  return CMDIFrameWnd::OnCreateClient(lpcs, pContext);
}

void CMainFrame::OnSize(UINT nType, int cx, int cy) 
{
	CMDIFrameWnd::OnSize(nType, cx, cy);
	
  m_split.SetWindowPos(&wndTop, 50, 50, 100, 100, SWP_SHOWWINDOW); // again, as you like it...
}

#define COLUMN9 0x00100L