Re: iterator default constructor
John Hickin wrote:
"n2xssvv g02gfr12930" <n2xssvv.g02gfr12930@ntlworld.com> wrote in message
news:hVyeg.7318$sX1.4680@newsfe1-gui.ntli.net...
I can't find anything in the standard that states that the default
constructor for an iterator will ensure it's invalid. This would seem to
be the common sense thing to do, so has the standard or myself missed
out on some detail?
It is covered in 21.4 Iterator requirements /5. Basically an iterator that
is not associated with any container has a _singular value_. By singular
value I think you can think in terms of random value. It is not
dereferencable.
Regards, John.
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html ]
I read that, but why not default construct the iterator to the
equivalent of a NULL pointer. This is what is done in gcc 3.3 and
probably a lot of other STL implementations, but as you've pointed out
the standard as no requirement for this. At least with a NULL pointer
you're going to get an exception if you try to dereference it, which is
why I generally reset them to NULL when not in use.
JB
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html ]