Jonathan Wakely <cow@compsoc.man.ac.uk> writes:
On Wed, Jun 15, 2005 at 10:24:10AM +0200, Thorsten Ottosen wrote:
"David Abrahams" <dave@boost-consulting.com> wrote in message news:uk6kws88y.fsf@boost-consulting.com...
| 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 www.boost-consulting.com