Re: hashed containers

From:
"James Kanze" <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Sun, 25 Feb 2007 12:30:29 CST
Message-ID:
<1172426287.066945.282750@z35g2000cwz.googlegroups.com>
On Feb 25, 6:49 pm, "Mitesh" <oopsbab...@hotmail.com> wrote:

What makes hashed containers non-standard C++ containers. Is the mere
idea of using hash table makes them non-standard, which I assume not
or is it something else.


Simply the fact that they are not in the standard. The original
STL from Stepanov didn't contain them, and the proposal to add
them wasn't made until it was too late to fully take it into
consideration.

If it is something else will the C++ standard
make it available in future?


I'd say that the probability of their being in the next version
of the standard is about as close to 100% as possible. The
committee has voted to adopt them, and unless it votes to take
them back out (very, very unlikely, I think), they will be
there.

Note that unlike other associative containers, the performance
of a hash table strongly depends on the quality of your hashing
function. And that writing a good hashing function very
definitly requires knowing what you are doing. So I suspect
that most of the time, the current associative containers will
in fact represent a better solution.

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