Re: typename iterator_traits::pointer

From:

red floyd <no.spam@here.dude>

Newsgroups:

comp.lang.c++

Date:

Thu, 24 Jan 2008 12:58:44 -0800

Message-ID:

<d07mj.5309$Rg1.71@nlpi068.nbdc.sbc.com>

Ioannis Vranos wrote:

Bo Persson wrote:

Sure there is:

p = vec.begin().operator->();

A more natural way to write it, without the artificial requirment
of using operator->, would be:

p = &*vec.begin();

which is the usual technique for getting the address of an element,
given an iterator.

And what is the use/need of Iter.operator->()?

Nothing much for vector<int>, but might be useful for accessing the
members of vector<some_struct>.

May you provide a working example?

Sure.

#include <utility>
#include <vector>
#include <iostream>
#include <ostream>

int main()
{
     typedef std::vector< std::pair<int, int> > pairvec;
     pairvec v;

     for (int = 0; i < 10; ++i)
         v.push_back(std::make_pair(i, 2*i));

     for (pairvec::iterator it = v.begin();
          it != v.end();
          ++it)
     {
           std::cout << it->first << "," << it->second << "\n";
     }
     std::cout << std::endl;
     return 0;
}