iterating over an STL collection

	A set of data is represented in STL by a pair of
	iterators. The first iterator references the first
	element and the last iterator references one past
	the last element. This is represented in half-open
	interval notation as:

			[first, last)

	Iterating:

	Instead of the typical C iteration:

	for (i = 0; i < count; ++i)
	{
		arrayBase[i]; /* element */
	}

	In STL we use:

	for (i = first; i != last; ++i)
	{
		(*i);	// dereferenced object
	}

	Never dereference the "last" iterator. It can
	only be used for comparing with the "first"
	iterator.
	
		(*last) is undefined.