1<?xml version="1.0" encoding="utf-8" ?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6<meta name="generator" content="Docutils 0.5: http://docutils.sourceforge.net/" /> 7<title>Forward Traversal Concept</title> 8<link rel="stylesheet" href="../../../rst.css" type="text/css" /> 9</head> 10<body> 11<div class="document" id="forward-traversal-concept"> 12<h1 class="title">Forward Traversal Concept</h1> 13 14<!-- Copyright David Abrahams 2006. Distributed under the Boost --> 15<!-- Software License, Version 1.0. (See accompanying --> 16<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> 17<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Forward Traversal</em> 18concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> meeting the requirements of Default 19Constructible and Single Pass Iterator, the following expressions are 20valid and respect the stated semantics.</p> 21<table border="1" class="docutils"> 22<colgroup> 23<col width="38%" /> 24<col width="34%" /> 25<col width="27%" /> 26</colgroup> 27<thead valign="bottom"> 28<tr><th class="head" colspan="3">Forward Traversal Iterator Requirements (in addition to Default Constructible and Single Pass Iterator)</th> 29</tr> 30<tr><th class="head">Expression</th> 31<th class="head">Return Type</th> 32<th class="head">Assertion/Note</th> 33</tr> 34</thead> 35<tbody valign="top"> 36<tr><td><tt class="docutils literal"><span class="pre">X</span> <span class="pre">u;</span></tt></td> 37<td><tt class="docutils literal"><span class="pre">X&</span></tt></td> 38<td>note: <tt class="docutils literal"><span class="pre">u</span></tt> may have a 39singular value.</td> 40</tr> 41<tr><td><tt class="docutils literal"><span class="pre">++r</span></tt></td> 42<td><tt class="docutils literal"><span class="pre">X&</span></tt></td> 43<td><tt class="docutils literal"><span class="pre">r</span> <span class="pre">==</span> <span class="pre">s</span></tt> and <tt class="docutils literal"><span class="pre">r</span></tt> is 44dereferenceable implies 45<tt class="docutils literal"><span class="pre">++r</span> <span class="pre">==</span> <span class="pre">++s.</span></tt></td> 46</tr> 47<tr><td><tt class="docutils literal"><span class="pre">iterator_traits<X>::difference_type</span></tt></td> 48<td>A signed integral type representing 49the distance between iterators</td> 50<td> </td> 51</tr> 52<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal<X>::type</span></tt></td> 53<td>Convertible to 54<tt class="docutils literal"><span class="pre">forward_traversal_tag</span></tt></td> 55<td> </td> 56</tr> 57</tbody> 58</table> 59</div> 60<div class="footer"> 61<hr class="footer" /> 62<a class="reference external" href="ForwardTraversal.rst">View document source</a>. 63Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source. 64 65</div> 66</body> 67</html> 68