<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!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"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title></title><meta name="generator" content="DocBook XSL Stylesheets V1.74.0" /><meta name="keywords" content=" ISO C++ , library , algorithm " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="algorithms.html" title="Part IX. Algorithms" /><link rel="prev" href="algorithms.html" title="Part IX. Algorithms" /><link rel="next" href="bk01pt09ch20.html" title="Chapter 20. Mutating" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="algorithms.html">Prev</a> </td><th width="60%" align="center">Part IX. Algorithms </th><td width="20%" align="right"> <a accesskey="n" href="bk01pt09ch20.html">Next</a></td></tr></table><hr /></div><div class="preface" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title"><a id="id425058"></a></h2></div></div></div><p> The neatest accomplishment of the algorithms chapter is that all the work is done via iterators, not containers directly. This means two important things: </p><div class="orderedlist"><ol type="1"><li><p> Anything that behaves like an iterator can be used in one of these algorithms. Raw pointers make great candidates, thus built-in arrays are fine containers, as well as your own iterators. </p></li><li><p> The algorithms do not (and cannot) affect the container as a whole; only the things between the two iterator endpoints. If you pass a range of iterators only enclosing the middle third of a container, then anything outside that range is inviolate. </p></li></ol></div><p> Even strings can be fed through the algorithms here, although the string class has specialized versions of many of these functions (for example, <code class="code">string::find()</code>). Most of the examples on this page will use simple arrays of integers as a playground for algorithms, just to keep things simple. The use of <span class="emphasis"><em>N</em></span> as a size in the examples is to keep things easy to read but probably won't be valid code. You can use wrappers such as those described in the <a class="ulink" href="../23_containers/howto.html" target="_top">containers chapter</a> to keep real code readable. </p><p> The single thing that trips people up the most is the definition of <span class="emphasis"><em>range</em></span> used with iterators; the famous "past-the-end" rule that everybody loves to hate. The <a class="ulink" href="../24_iterators/howto.html#2" target="_top">iterators chapter</a> of this document has a complete explanation of this simple rule that seems to cause so much confusion. Once you get <span class="emphasis"><em>range</em></span> into your head (it's not that hard, honest!), then the algorithms are a cakewalk. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="algorithms.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="algorithms.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="bk01pt09ch20.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Part IX. Algorithms </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 20. Mutating</td></tr></table></div></body></html>