Re: reverse iterator and IntelliSense

From:
"Tom Widmer [VC++ MVP]" <tom_usenet@hotmail.com>
Newsgroups:
microsoft.public.vc.stl
Date:
Mon, 25 Feb 2008 13:32:20 +0000
Message-ID:
<OsoCaL7dIHA.2000@TK2MSFTNGP05.phx.gbl>
schliz wrote:

On 18 Feb., 09:24, Ulrich Eckhardt <eckha...@satorlaser.com> wrote:

schliz wrote:

On 15 Feb., 16:14, "Tom Widmer [VC++ MVP]" <tom_use...@hotmail.com>
wrote:

If you hover over (*it), intellisense picks up that you are hovering
over "it"...

So does it mean it is no internal thing, intelliSense always shows one
element behind?

No, I think he meant that hovering over 'it' will show a representation
of 'it'. Now, in order to understand that representation, you need to know
how reverse_iterators work (well, that point could be improved in the
debugger). In particular you should look at the base() memberfunction,
which indeed always points one element behind.

Uli


What I really don't understand, if you use (*r) the correct values are
copied.


I don't understand why you don't understand why correctly written code
works!

I think for debugging it is very stange.


a) A reverse iterator wraps a forwards iterator that points to the
element after the one the reverse iterator dereferences to. So operator*
looks something like this:

value_type& operator* const
{
   base_iterator i = base(); //get wrapped iterator
   return *--i; //return decrement base iterator before dereferencing!
}

b) If you hover over a reverse iterator, IntelliSense shows you the
member variable of the iterator, the wrapped one mentioned above.

Do you understand now?

Tom

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