1.. Copyright David Abrahams 2006. Distributed under the Boost 2.. Software License, Version 1.0. (See accompanying 3.. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 4 5Forward Traversal Concept 6......................... 7 8A class or built-in type ``X`` models the *Forward Traversal* 9concept if, in addition to ``X`` meeting the requirements of Default 10Constructible and Single Pass Iterator, the following expressions are 11valid and respect the stated semantics. 12 13+--------------------------------------------------------------------------------------------------------+ 14|Forward Traversal Iterator Requirements (in addition to Default Constructible and Single Pass Iterator) | 15+---------------------------------------+-----------------------------------+----------------------------+ 16|Expression |Return Type |Assertion/Note | 17+=======================================+===================================+============================+ 18|``X u;`` |``X&`` |note: ``u`` may have a | 19| | |singular value. | 20+---------------------------------------+-----------------------------------+----------------------------+ 21|``++r`` |``X&`` |``r == s`` and ``r`` is | 22| | |dereferenceable implies | 23| | |``++r == ++s.`` | 24+---------------------------------------+-----------------------------------+----------------------------+ 25|``iterator_traits<X>::difference_type``|A signed integral type representing| | 26| |the distance between iterators | | 27| | | | 28+---------------------------------------+-----------------------------------+----------------------------+ 29|``iterator_traversal<X>::type`` |Convertible to | | 30| |``forward_traversal_tag`` | | 31+---------------------------------------+-----------------------------------+----------------------------+ 32