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>

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>

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>

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>

<H1>ERROR</H1>
<H2>The requested URL could not be retrieved</H2>
<HR>
<P>
While trying to retrieve the URL:
<A HREF="www.mycurrentclient.com:0">www.mycurrentclient.com:0</A>
<P>
The following error was encountered:
<UL>
<LI>

Invalid URL

</UL>

<P>
Some aspect of the requested URL is incorrect.  Possible problems:
<UL>
<LI>Missing or incorrect access protocol (should be `http://'' or similar)
<LI>Missing hostname
<LI>Illegal double-escape in the URL-Path
<LI>Illegal character in hostname; underscores are not allowed
</UL>
<P>Your cache administrator is <A HREF="mailto:root">root</A>. 

<br clear="all">

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>

void DrawTransparent(HDC hDC, int x, int y, int nWidth, int nHeight, HBITMAP hBitmap, COLORREF crColour)
{
	_ASSERTE(hDC != NULL);
	_ASSERTE(hBitmap != NULL);

	COLORREF crOldBack = SetBkColor(hDC, RGB(255,255,255));
	COLORREF crOldText = SetTextColor(hDC, RGB(0,0,0));

	HDC dcImage, dcMask, dcMem;
	// Create two memory dcs for the image and the mask
	dcImage = CreateCompatibleDC(hDC);
	dcMask  = CreateCompatibleDC(hDC);
	dcMem   = CreateCompatibleDC(hDC);

	HBITMAP hOldMemBitmap = (HBITMAP) SelectObject(dcMem, hBitmap);

	// Create bitmap copy
	HBITMAP hBitmapImage = CreateCompatibleBitmap(hDC, nWidth, nHeight);

	// Select the image into the appropriate dc
	HBITMAP hOldBitmapImage = (HBITMAP) SelectObject(dcImage, hBitmapImage);

	HBITMAP bitmapMask = CreateBitmap(nWidth, nHeight, 1, 1, NULL);

	// Select the mask bitmap into the appropriate dc
	HBITMAP hOldBitmapMask = (HBITMAP) SelectObject(dcMask, bitmapMask);

	// Build mask based on transparent colour
	BitBlt(dcImage, 0, 0, nWidth, nHeight, dcMem, 0, 0, SRCCOPY);

	SetBkColor(dcImage, crColour);
	BitBlt(dcMask, 0, 0, nWidth, nHeight, dcImage, 0, 0, SRCCOPY);

	// Do the work - True Mask method - cool if not actual display
	BitBlt(hDC, x, y, nWidth, nHeight, dcImage, 0, 0, SRCINVERT);
	BitBlt(hDC, x, y, nWidth, nHeight, dcMask,  0, 0, SRCAND);
	BitBlt(hDC, x, y, nWidth, nHeight, dcImage, 0, 0, SRCINVERT);

	// Restore settings
	SelectObject(dcImage, hOldBitmapImage);
	SelectObject(dcMask,  hOldBitmapMask);
	SelectObject(dcMem, hOldMemBitmap);

	DeleteObject(hBitmapImage);
	DeleteObject(bitmapMask);

	DeleteDC( dcMem );
	DeleteDC( dcMask );
	DeleteDC( dcImage );

	SetBkColor(hDC, crOldBack);
	SetTextColor(hDC, crOldText);
}

ÿVOTD: 8 "Love never fails. But where there are prophecies, they will cease;
where there are tongues, they will be stilled; where there is knowledge, it will pass away." - 1 Cor 13:8 (NIV)