Re: Using range-based for with alternative ranges

From:
Juha Nieminen <nospam@thanks.invalid>
Newsgroups:
comp.lang.c++
Date:
Fri, 18 May 2012 18:17:46 +0000 (UTC)
Message-ID:
<jp63oa$huj$1@speranza.aioe.org>
Juha Nieminen <nospam@thanks.invalid> wrote:

It's a bit complicated and verbose, and I was wondering if a simpler
solution could be possible (and also if this could be done with one
single class rather than having to use two).


  This is slightly simpler:

//-------------------------------------------------------------------
#include <iterator>

template<typename Iter_t>
struct RangeWrapper
{
    Iter_t mBegin, mEnd;
    RangeWrapper(Iter_t b, Iter_t e): mBegin(b), mEnd(e) {}
    Iter_t begin() { return mBegin; }
    Iter_t end() { return mEnd; }
};

template<typename Container_t>
RangeWrapper<typename Container_t::reverse_iterator>
revRange(Container_t& container)
{
    return { container.rbegin(), container.rend() };
}

template<typename Elem_t, std::size_t size>
RangeWrapper<std::reverse_iterator<Elem_t*>>
revRange(Elem_t (&array)[size])
{
    typedef std::reverse_iterator<Elem_t*> Iter_t;
    return { Iter_t(array + size), Iter_t(array) };
}
//-------------------------------------------------------------------

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