Re: Cannot Use GUID in map
Hendrik Schober <SpamTrap@gmx.de> wrote:
Igor Tandetnik <itandetnik@mvps.org> wrote:
"David Wilkinson" <no-reply@effisols.com> wrote in message
news:uRtQ2LhzIHA.5892@TK2MSFTNGP02.phx.gbl
Igor Tandetnik wrote:
Map keys have to be comparable. By default, map tries to use
built-in less-than (<) operator, but that doesn't work with GUIDs.
You need to define your own comparator, and pass it as the third
template parameter.
You can define operator <() for GUID's, no?
I guess, but personally I wouldn't want to. Too obscure. I'd rather
have an explicit comparator.
Why would consider this too obscure? Is this just a gut
feeling or can you define what makes it too obscure?
Gut feeling, mostly. I don't like overloaded operators, except in cases
where the operator has a clear widely accepted meaning (like operator*
for class Matrix). In particular, unless instances of a class represent
something naturally orderable (e.g. class BigInt), I don't like
overloading operator< just for convenience of using STL containers and
such. The ordering for such classes is usually an artificial construct,
and I prefer to give it a descriptive name.
--
With best wishes,
Igor Tandetnik
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