Re: pointer iterator interaction

From:
Ian Collins <ian-news@hotmail.com>
Newsgroups:
comp.lang.c++
Date:
Fri, 30 Jun 2006 23:06:59 +1200
Message-ID:
<4gkeujF1ne9isU9@individual.net>
silversurfer wrote:

Ok, this should be fairly easy for most of you (at least I hope so),
but not for me:

Let us say we have got the following elements:
    std::vector<Entry> models; //Entry is a struct
    std::vector<Entry>::iterator modelIterator;

In a method, I am currently writing, I need to get a pointer to an
entry in the vector.. I thought of the following:

Entry* MyObject::getNextEntry() {
    Entry* tmpEntry;

    if (modelIterator == models.end()) {
        return NULL;
    } else {
        tmpEntry = modelIterator;
        modelIterator++;
        return tmpEntry;
    }
}

Unfortunately, this does not work, I get the error message:
   error: cannot convert `
       __gnu_cxx::__normal_iterator<Entry*, std::vector<Entry,
       std::allocator<Entry> > >' to `Entry*' in assignment

I do not really understand this: As far as I understood it, an iterator
should be a pointer to the elements of the vector, and tmpEntry in the
mehtod above is nothing else than this..


No, it might be and in some implementation is is, but it doesn't have to be.

How can I get a pointer to the element to which the iterator is
currently pointing?


&(*modelIterator);

should do it.

--
Ian Collins.

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