diff options
Diffstat (limited to 'libstdc++-v3/doc/html/25_algorithms/howto.html')
| -rw-r--r-- | libstdc++-v3/doc/html/25_algorithms/howto.html | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/libstdc++-v3/doc/html/25_algorithms/howto.html b/libstdc++-v3/doc/html/25_algorithms/howto.html new file mode 100644 index 00000000000..bb5caee354a --- /dev/null +++ b/libstdc++-v3/doc/html/25_algorithms/howto.html @@ -0,0 +1,116 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!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" xml:lang="en" lang="en"> +<head> + <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> + <meta name="AUTHOR" content="pme@gcc.gnu.org (Phil Edwards)" /> + <meta name="KEYWORDS" content="HOWTO, libstdc++, GCC, g++, libg++, STL" /> + <meta name="DESCRIPTION" content="HOWTO for the libstdc++ chapter 25." /> + <meta name="GENERATOR" content="vi and eight fingers" /> + <title>libstdc++ HOWTO: Chapter 25: Algorithms</title> +<link rel="StyleSheet" href="../lib3styles.css" type="text/css" /> +<link rel="Start" href="../documentation.html" type="text/html" + title="GNU C++ Standard Library" /> +<link rel="Prev" href="../24_iterators/howto.html" type="text/html" + title="Iterators" /> +<link rel="Next" href="../26_numerics/howto.html" type="text/html" + title="Numerics" /> +<link rel="Copyright" href="../17_intro/license.html" type="text/html" /> +<link rel="Help" href="../faq/index.html" type="text/html" title="F.A.Q." /> +</head> +<body> + +<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> + + +<!-- ####################################################### --> +<hr /> +<h1>Contents</h1> +<ul> + <li><a href="#1">Prerequisites</a></li> + <li><a href="#2">Special <code>swap</code>s</a></li> +</ul> + +<hr /> + +<!-- ####################################################### --> + +<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: + </p> + <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, as well as your own iterators. + </li> + <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. + </li> + </ol> + <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>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. + <a name="Nsize">The use of <strong>N</strong></a> 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 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 + "past-the-end" rule that everybody loves to hate. The + <a href="../24_iterators/howto.html#2">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>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">Special <code>swap</code>s</a></h2> + <p>If you call <code> std::swap(x,y); </code> where x and y are standard + containers, then the call will automatically be replaced by a call to + <code> x.swap(y); </code> instead. + </p> + <p>This allows member functions of each container class to take over, and + containers' swap functions should have O(1) complexity according to + the standard. (And while "should" allows implementations to + behave otherwise and remain compliant, this implementation does in + fact use constant-time swaps.) This should not be surprising, since + for two containers of the same type to swap contents, only some + internal pointers to storage need to be exchanged. + </p> + <p>Return <a href="#top">to top of page</a> or + <a href="../faq/index.html">to the FAQ</a>. + </p> + + + + +<!-- ####################################################### --> + +<hr /> +<p class="fineprint"><em> +See <a href="../17_intro/license.html">license.html</a> for copying conditions. +Comments and suggestions are welcome, and may be sent to +<a href="mailto:libstdc++@gcc.gnu.org">the libstdc++ mailing list</a>. +</em></p> + + +</body> +</html> |
