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   <TITLE>libstdc++-v3 HOWTO:  Chapter 25</TITLE>
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<H1 CLASS="centered"><A NAME="top">Chapter 25:  Algorithms</A></H1>

<P>Chapter 25 deals with the generalized subroutines for automatically
   transforming lemmings into gold.
</P>


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<H1>Contents</H1>
<UL>
   <LI><A HREF="#1">Prerequisites</A>
   <LI><A HREF="#2">Topic</A>
</UL>

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<H2><A NAME="1">Prerequisites</A></H2>
   <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:
      <OL>
        <LI>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.  So do your own iterators.
        <LI>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.
      </OL>
   </P>
   <P>Even strings can be fed through the algorithms here, although the
      string class has specialized versions of many of these functions (for
      example, <TT>string::find()</TT>).  Most of the examples on this
      page will use simple arrays of integers as a playground for
      algorithms, just to keep things simple.
      <A NAME="Nsize">The use of <B>N</B></A> as a size in the examples is
      to keep things easy to read but probably won't be legal code.  You can
      use wrappers such as those described in the
      <A HREF="../23_containers/howto.html">containers chapter</A> to keep
      real code readable.
   </P>
   <P>The single thing that trips people up the most is the definition of
      <EM>range</EM> used with iterators; the famous
      &quot;past-the-end&quot; rule that everybody loves to hate.  The
      <A HREF="../24_iterators/howto.html">iterators chapter</A> of this
      document has a complete explanation of this simple rule that seems to
      cause so much confusion.  Once you get <EM>range</EM> into your head
      (it's not that hard, honest!), then the algorithms are a cakewalk.
   </P>
   <P>
   </P>
   <P>Return <A HREF="#top">to top of page</A> or
      <A HREF="../faq/index.html">to the FAQ</A>.
   </P>

<HR>
<H2><A NAME="2">Topic</A></H2>
   <P>Blah.
   </P>
   <P>Return <A HREF="#top">to top of page</A> or
      <A HREF="../faq/index.html">to the FAQ</A>.
   </P>


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<P CLASS="fineprint"><EM>
Comments and suggestions are welcome, and may be sent to
<A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A> or
<A HREF="mailto:gdr@gcc.gnu.org">Gabriel Dos Reis</A>.
<BR> $Id: howto.html,v 1.5 2000/12/03 23:47:48 jsm28 Exp $
</EM></P>


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