Re: Is STL iterator singleton ?

From:
=?ISO-8859-1?Q?Erik_Wikstr=F6m?= <Erik-wikstrom@telia.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 08 Aug 2007 09:05:33 GMT
Message-ID:
<xHfui.5782$ZA.2490@newsb.telia.net>
On 2007-08-08 06:00, raan wrote:

Is iterators singleton?

I am accessing a map through wrapper functions to it; that allow me to
access the contents of the map as

CUnit &unit = hash.getFirstunit();
while(hash.hasMoreunits())
{
    unit = hash.getNextUnit();
}

Thats all about it. A call to getFirstUnit will initialize the
iterator. hasMoreUnits will move the iterator one unit forward and
hasNextUnit will access the next one and so on.


To answer the question in the subject, no.

What I really want to know is how you implemented that wrapper to get
that kind of functionality, using global variables? My advice, if you
insist on keeping the code like that, is to make hasMoreUnits() and
getNextUnit() take a CUnit as parameter so they know which iterator to
test for end / increment.

If the problem you are trying to solve is to iterate over your home-made
hashmap then perhaps you should instead you should try to create a STL-
compatible iterator (i.e. one that behaves like other iterators). I've
done it, so it's quite possible.

--
Erik Wikstr?m

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