Problem with Boost iterators

From:
michael.alexeev@gmail.com
Newsgroups:
comp.lang.c++.moderated
Date:
1 Nov 2006 03:10:54 -0500
Message-ID:
<1162348295.249095.231880@e64g2000cwd.googlegroups.com>
Hi all,

I am running into the compilation error (gcc 4.0.2 Suse Linux) while
trying to compile the following simple program:

#include <boost/iterator/iterator_facade.hpp>

struct Pixel { int _abc;};

class PixelIterator :
  public boost::iterator_facade< PixelIterator, Pixel,
boost::random_access_traversal_tag >
{
public:
  friend class boost::iterator_core_access;
  explicit PixelIterator() : _prPixel() {}
  explicit PixelIterator(Pixel * iprPixel) : _prPixel(iprPixel) {}
  void increment(){++_prPixel;}
  void decrement(){--_prPixel;}
  bool equal(const PixelIterator& iOther) const{ return _prPixel ==
iOther._prPixel; }
  Pixel& dereference() const{return *_prPixel;}
  void advance(int iDist){_prPixel += iDist;}
  uint distance_to(const PixelIterator& iOther) const{return
iOther._prPixel - _prPixel;}
private:
  Pixel * _prPixel;
};

int main()
{
  Pixel p[10];
  PixelIterator it(p);
  it[1]._abc = 1;
}

The error message is
 'class boost::detail::operator_brackets_proxy<PixelIterator>' has
no member named '_abc

The Boost website is currently unavailable to look-up the documentation
but I am pretty match sure that the semantic of operator[] (int dist)
is *(it +dist). And indeed if I replace the last line in main with
(*(it+1))._abc = 1;

the error goes away.

Any help is greatly appreciated.
Mike

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