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<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 V1.75.2" /><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.
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Algorithms
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</th><td width="20%" align="right"> <a accesskey="n" href="bk01pt09ch20.html">Next</a></td></tr></table><hr /></div><div class="preface"><div class="titlepage"><div><div><h2 class="title"><a id="id638172"></a></h2></div></div></div><p>
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The neatest accomplishment of the algorithms chapter is that all the
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work is done via iterators, not containers directly. This means two
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important things:
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</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>
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Anything that behaves like an iterator can be used in one of
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these algorithms. Raw pointers make great candidates, thus
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built-in arrays are fine containers, as well as your own iterators.
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</p></li><li class="listitem"><p>
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The algorithms do not (and cannot) affect the container as a
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whole; only the things between the two iterator endpoints. If
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you pass a range of iterators only enclosing the middle third of
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a container, then anything outside that range is inviolate.
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</p></li></ol></div><p>
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Even strings can be fed through the algorithms here, although the
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string class has specialized versions of many of these functions
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(for example, <code class="code">string::find()</code>). Most of the examples
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on this page will use simple arrays of integers as a playground
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for algorithms, just to keep things simple. The use of
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<span class="emphasis"><em>N</em></span> as a size in the examples is to keep
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things easy to read but probably won't be valid code. You can
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use wrappers such as those described in the <a class="link" href="containers.html" title="Part VII. Containers">containers chapter</a> to
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keep real code readable.
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</p><p>
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The single thing that trips people up the most is the definition
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of <span class="emphasis"><em>range</em></span> used with iterators; the famous
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"past-the-end" rule that everybody loves to hate. The
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<a class="link" href="iterators.html" title="Part VIII. Iterators">iterators
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chapter</a> of this document has a complete explanation of
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this simple rule that seems to cause so much confusion. Once you
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get <span class="emphasis"><em>range</em></span> into your head (it's not that
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hard, honest!), then the algorithms are a cakewalk.
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</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.
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Algorithms
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</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>
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