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- .. Copyright David Abrahams 2006. Distributed under the Boost
- .. Software License, Version 1.0. (See accompanying
- .. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- Forward Traversal Concept
- .........................
- A class or built-in type ``X`` models the *Forward Traversal*
- concept if, in addition to ``X`` meeting the requirements of Default
- Constructible and Single Pass Iterator, the following expressions are
- valid and respect the stated semantics.
- +--------------------------------------------------------------------------------------------------------+
- |Forward Traversal Iterator Requirements (in addition to Default Constructible and Single Pass Iterator) |
- +---------------------------------------+-----------------------------------+----------------------------+
- |Expression |Return Type |Assertion/Note |
- +=======================================+===================================+============================+
- |``X u;`` |``X&`` |note: ``u`` may have a |
- | | |singular value. |
- +---------------------------------------+-----------------------------------+----------------------------+
- |``++r`` |``X&`` |``r == s`` and ``r`` is |
- | | |dereferenceable implies |
- | | |``++r == ++s.`` |
- +---------------------------------------+-----------------------------------+----------------------------+
- |``iterator_traits<X>::difference_type``|A signed integral type representing| |
- | |the distance between iterators | |
- | | | |
- +---------------------------------------+-----------------------------------+----------------------------+
- |``iterator_traversal<X>::type`` |Convertible to | |
- | |``forward_traversal_tag`` | |
- +---------------------------------------+-----------------------------------+----------------------------+
|
