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> 18 concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> meeting the requirements of Default 19 Constructible and Single Pass Iterator, the following expressions are 20 valid 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 39 singular 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 44 dereferenceable 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 49 the 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>. 63 Generated 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