libs/iterator/doc/ForwardTraversal.rst
.. 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`` | | +---------------------------------------+-----------------------------------+----------------------------+