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From: David Abrahams (dave_at_[hidden])
Date: 2005-06-15 11:01:27

Jonathan Wakely <cow_at_[hidden]> writes:

> On Wed, Jun 15, 2005 at 10:24:10AM +0200, Thorsten Ottosen wrote:
>> "David Abrahams" <dave_at_[hidden]> wrote in message
>> | If someone would clearly and succinctly spell out the question, I'd be
>> | happy to.
>> should one be able to add, subtract, and compare mutable random access
>> iterators with
>> random access const_iterators provided they point to the same container?
> It's not required for any iterator in general (you can't convert all
> output iterators to input iterators, for instance ostream_iterator
> cannot be converted to a read-only iterator type).
> But the container requirements require that X::iterator be convertible
> to X::const_iterator, and then all those operations work by using that
> conversion.

That's incorrect. For example, if the operations are templated no
implicit conversion will take place.

Dave Abrahams
Boost Consulting

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