Re: VC9: STL: hash_set/map : hash_compare without operator < ???

From:
"Scot T Brennecke" <ScotB@MVPs.spamhater.org>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 20 May 2009 21:46:21 -0500
Message-ID:
<#D$zU5b2JHA.4416@TK2MSFTNGP05.phx.gbl>
If you don't care about ordering, then you don't care if you implement one arbitrarily right? Just
make up something that will be consistent and symmetric, even if you won't use it.

"mario semo" <mario_semo@hotmail.com> wrote in message
news:7E0A5229-3B5D-4B84-BC7B-647411F47979@microsoft.com...

"Ben Voigt [C++ MVP]" <bvoigt@newsgroup.nospam> schrieb im Newsbeitrag
news:uZJr2bW2JHA.1716@TK2MSFTNGP03.phx.gbl...

which of the relation rules are not fullfilled with my implementation?
irreflexive : yes, it is. (foreach(x): f(x,x)=false) is true.
antisymetric : yes. (forany (x,y with x!=y) f(x,y) or f(y,x) is
false. ) is true


You might double check on that antisymmetric one.


Ben, Ulrich. , yes, i see. definitly my f(x,y) is symetric. f(x,y)==f(y,x) always.

Earlier versions of (STL or Template Lib) didnt need a less(x,y) function, but just an equal_to()
function.

is there any collection in the STL (or whatever it is called) of MSVC++ which can be used for
elements which does not implement an ordering? i can compare all my elements (equal or not equal)
but i cannot say which object is less than the other object.

it looks as i still have to use my own hash table implementations :-(

mario.

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