<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Bidirectional Range</title> <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="../../index.html" title="Chapter 1. Range 2.0"> <link rel="up" href="../concepts.html" title="Range Concepts"> <link rel="prev" href="forward_range.html" title="Forward Range"> <link rel="next" href="random_access_range.html" title="Random Access Range"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> <td align="center"><a href="../../../../../../index.html">Home</a></td> <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="forward_range.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../concepts.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="random_access_range.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="range.concepts.bidirectional_range"></a><a class="link" href="bidirectional_range.html" title="Bidirectional Range">Bidirectional Range</a> </h3></div></div></div> <a name="range.concepts.bidirectional_range.notation"></a><h5> <a name="id762089"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.notation">Notation</a> </h5> <div class="informaltable"><table class="table"> <colgroup> <col> <col> </colgroup> <thead><tr></tr></thead> <tbody> <tr> <td> <p> <code class="computeroutput"><span class="identifier">X</span></code> </p> </td> <td> <p> A type that is a model of <a class="link" href="bidirectional_range.html" title="Bidirectional Range">Bidirectional Range</a>. </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">a</span></code> </p> </td> <td> <p> Object of type X. </p> </td> </tr> </tbody> </table></div> <a name="range.concepts.bidirectional_range.description"></a><h5> <a name="id762184"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.description">Description</a> </h5> <p> This concept provides access to iterators that traverse in both directions (forward and reverse). The <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> iterator must meet all of the requirements of <a href="../../../../../../libs/iterator/doc/new-iter-concepts.html#bidirectional-traversal-iterators-lib-bidirectional-traversal-iterators" target="_top">Bidirectional Traversal Iterator</a>. </p> <a name="range.concepts.bidirectional_range.refinement_of"></a><h5> <a name="id762247"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.refinement_of">Refinement of</a> </h5> <p> <a class="link" href="forward_range.html" title="Forward Range">Forward Range</a> </p> <a name="range.concepts.bidirectional_range.associated_types"></a><h5> <a name="id762274"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.associated_types">Associated types</a> </h5> <div class="informaltable"><table class="table"> <colgroup> <col> <col> <col> </colgroup> <thead><tr></tr></thead> <tbody> <tr> <td> <p> Reverse Iterator type </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> The type of iterator used to iterate through a Range's elements in reverse order. The iterator's value type is expected to be the Range's value type. A conversion from the reverse iterator type to the const reverse iterator type must exist. </p> </td> </tr> <tr> <td> <p> Const reverse iterator type </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> </p> </td> <td> <p> A type of reverse iterator that may be used to examine, but not to modify, a Range's elements. </p> </td> </tr> </tbody> </table></div> <a name="range.concepts.bidirectional_range.valid_expressions"></a><h5> <a name="id762436"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.valid_expressions">Valid expressions</a> </h5> <div class="informaltable"><table class="table"> <colgroup> <col> <col> <col> <col> </colgroup> <thead><tr> <th> <p> Name </p> </th> <th> <p> Expression </p> </th> <th> <p> Return type </p> </th> <th> <p> Semantics </p> </th> </tr></thead> <tbody> <tr> <td> <p> Beginning of range </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rbegin</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> if <code class="computeroutput"><span class="identifier">a</span></code> is mutable <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> otherwise. </p> </td> <td> <p> Equivalent to <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">a</span><span class="special">))</span></code>. </p> </td> </tr> <tr> <td> <p> End of range </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rend</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> if <code class="computeroutput"><span class="identifier">a</span></code> is mutable, <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span></code> otherwise. </p> </td> <td> <p> Equivalent to <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_reverse_iterator</span><span class="special"><</span><span class="identifier">X</span><span class="special">>::</span><span class="identifier">type</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">a</span><span class="special">))</span></code>. </p> </td> </tr> </tbody> </table></div> <a name="range.concepts.bidirectional_range.complexity_guarantees"></a><h5> <a name="id762894"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.complexity_guarantees">Complexity guarantees</a> </h5> <p> <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rbegin</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> has the same complexity as <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> and <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rend</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> has the same complexity as <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> from <a class="link" href="forward_range.html" title="Forward Range">Forward Range</a>. </p> <a name="range.concepts.bidirectional_range.invariants"></a><h5> <a name="id763034"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.invariants">Invariants</a> </h5> <div class="informaltable"><table class="table"> <colgroup> <col> <col> </colgroup> <thead><tr></tr></thead> <tbody> <tr> <td> <p> Valid reverse range </p> </td> <td> <p> For any Bidirectional Range a, <code class="computeroutput"><span class="special">[</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rbegin</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rend</span><span class="special">(</span><span class="identifier">a</span><span class="special">))</span></code> is a valid range, that is, <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rend</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> is reachable from <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rbegin</span><span class="special">(</span><span class="identifier">a</span><span class="special">)</span></code> in a finite number of increments. </p> </td> </tr> <tr> <td> <p> Completeness </p> </td> <td> <p> An algorithm that iterates through the range <code class="computeroutput"><span class="special">[</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rbegin</span><span class="special">(</span><span class="identifier">a</span><span class="special">),</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">rend</span><span class="special">(</span><span class="identifier">a</span><span class="special">))</span></code> will pass through every element of <code class="computeroutput"><span class="identifier">a</span></code>. </p> </td> </tr> </tbody> </table></div> <a name="range.concepts.bidirectional_range.see_also"></a><h5> <a name="id763287"></a> <a class="link" href="bidirectional_range.html#range.concepts.bidirectional_range.see_also">See also</a> </h5> <p> <a class="link" href="../reference/concept_implementation/semantics/metafunctions.html" title="Metafunctions">Implementation of metafunctions</a> </p> <p> <a class="link" href="../reference/concept_implementation/semantics/functions.html" title="Functions">Implementation of functions</a> </p> </div> <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> <td align="left"></td> <td align="right"><div class="copyright-footer">Copyright © 2003 -2010 Thorsten Ottosen, Neil Groves<p> Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="forward_range.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../concepts.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="random_access_range.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>