Managed C++/CLI

<code>
int main()
{
	// This causes error C2065, because compiler doesn't know 
	// identifier "x".
	int i = 100 * x; 
}
</code>

<code>
int main()
{
	// Here we declare (tell compiler that identifier "x" means integer value) and 
	// define (tell compiler that identifier "x" value is 1) identifier "x"
	int x = 1;
	// Now this doesn't cause any problems, because compiler a) knows identifier x and
	// b) there is assigned value for identifier "x" (actually C++ compiler doesn't know 
	// this, and forgetting to give actuall value for identifier "x" would cause random 	// runtime behaviour a.k.a. bugs)
	int i = 100 * x; 
}
</code>

<code>
LONGLONG done = 0;
UINT size = BUFFERSIZE;
BYTE buffer[BUFFERSIZE];

int theFile = _tsopen(pCRCSt->FileName, _O_RDONLY | _O_SEQUENTIAL | _O_BINARY, _SH_DENYWR);
if (theFile != -1)
{ 
	// Getting file length and storing it to length value. 
	// 
	// SEEK_END sets position to the end of file. 
	// 
	// _lseek returns the offset in a 64-bit integer, in bytes, of the new position 
	// from the beginning of the file (in this case it returns length of file, 
	// because we set seek position to END OF FILE).
	// 
	long length = _lseeki64( theFile, 0L, SEEK_END );
	if( length == -1L )
	{
		// The function returns –1L to indicate an error and sets errno.

		// Avoid file processing, but close file
		size = 0L;

		// Specific error handlers
		switch( errno )
		{
			case EBADF:
				// File descriptor is invalid
				// TODO: ADD EXTRA ERROR HANDLING
				// For example: throw exception or show message box for user.
				break;
			
			case EINVAL:
				// Value for origin is invalid or the position
				// specified by offset is before the beginning of the file.
				// TODO: ADD EXTRA ERROR HANDLING
				// For example: throw exception or show message box for user.
				break;
			
			default:
				// Unknown error code				
				// TODO: ADD EXTRA ERROR HANDLING
				// For example: throw exception or show message box for user.
				break;			
		}
	}
	if( length <= 0 )
	{
		// On devices incapable of 
		// seeking (such as terminals and printers), the return value 
		// is undefined.
		length = 1L;
	}


	// Move file reading position to beginning of the file. 
	_lseeki64 (theFile, 0L, SEEK_SET); 
	while (size == BUFFERSIZE)
	{
		size = _read(theFile, buffer, BUFFERSIZE);
		if (size)
		{
			pCRCSt->pCRC_32->Calculate(buffer, size, CRC);
			if (::IsWindow(Progress))
			{
				//update progcess bar
				done += size;
				int percent = (int) (((long double)done / (long double)length) * 100); 
				::PostMessage(Progress, PBM_SETPOS, percent, 0);
			}
		} 
	} 

	// Close file (this is important. Error handlers need to make sure that this is allways called.)
	close(theFile);
} 

</code>