<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" /> <title>The MPL Reference Manual: Concepts</title> <link rel="stylesheet" href="../style.css" type="text/css" /> </head> <body class="docframe refmanual"> <table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./iterators.html" class="navigation-link">Prev</a> <a href="./forward-iterator.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./iterator-metafunctions.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./iterators.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> <td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./iterators.html" class="navigation-link">Iterators</a> / <a href="./iterators-concepts.html" class="navigation-link">Concepts</a></td> </tr></table><div class="header-separator"></div> <div class="section" id="id382"> <h1><a class="toc-backref" href="./iterators.html#id1449"><a class="subsection-title" href="#concepts" name="concepts">Concepts</a></a></h1> <p id="label-iterators-concepts">All iterators in MPL are classified into three iterator concepts, or <cite>categories</cite>, named according to the type of traversal provided. The categories are: <a class="reference internal" href="./forward-iterator.html">Forward Iterator</a>, <a class="reference internal" href="./bidirectional-iterator.html">Bidirectional Iterator</a>, and <a class="reference internal" href="./random-access-iterator.html">Random Access Iterator</a>. The concepts are hierarchical: <a class="reference internal" href="./random-access-iterator.html">Random Access Iterator</a> is a refinement of <a class="reference internal" href="./bidirectional-iterator.html">Bidirectional Iterator</a>, which, in its turn, is a refinement of <a class="reference internal" href="./forward-iterator.html">Forward Iterator</a>.</p> <p>Because of the inherently immutable nature of the value access, MPL iterators escape the problems of the traversal-only categorization discussed at length in <a class="citation-reference" href="#n1550" id="id383">[n1550]</a>.</p> <table class="docutils citation" frame="void" id="n1550" rules="none"> <colgroup><col class="label" /><col /></colgroup> <tbody valign="top"> <tr><td class="label"><a class="fn-backref" href="#id383">[n1550]</a></td><td><a class="reference external" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2003/n1550.htm" target="_top">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2003/n1550.htm</a></td></tr> </tbody> </table> <!-- Iterators/Concepts//Forward Iterator |10 --> <ul class="toc simple" id="outline"> <li><a class="reference internal" href="./forward-iterator.html" id="id1450">Forward Iterator</a></li> <li><a class="reference internal" href="./bidirectional-iterator.html" id="id1451">Bidirectional Iterator</a></li> <li><a class="reference internal" href="./random-access-iterator.html" id="id1452">Random Access Iterator</a></li> </ul> </div> <div class="footer-separator"></div> <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./iterators.html" class="navigation-link">Prev</a> <a href="./forward-iterator.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./iterator-metafunctions.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./iterators.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> <td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body> </html>