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| author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
|---|---|---|
| committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
| commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
| tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libstdc++-v3/doc/html/manual/containers.html | |
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| -rw-r--r-- | libstdc++-v3/doc/html/manual/containers.html | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/libstdc++-v3/doc/html/manual/containers.html b/libstdc++-v3/doc/html/manual/containers.html new file mode 100644 index 000000000..1185af6a1 --- /dev/null +++ b/libstdc++-v3/doc/html/manual/containers.html @@ -0,0 +1,55 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Chapter 9. Containers</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" ISO C++ , library "/><link rel="home" href="../spine.html" title="The GNU C++ Library"/><link rel="up" href="bk01pt02.html" title="Part II. Standard Contents"/><link rel="prev" href="facets.html" title="Facets"/><link rel="next" href="associative.html" title="Associative"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 9. + Containers + +</th></tr><tr><td align="left"><a accesskey="p" href="facets.html">Prev</a> </td><th width="60%" align="center">Part II. + Standard Contents + </th><td align="right"> <a accesskey="n" href="associative.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 9. Containers"><div class="titlepage"><div><div><h2 class="title"><a id="std.containers"/>Chapter 9. + Containers + <a id="id478750" class="indexterm"/> +</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="containers.html#std.containers.sequences">Sequences</a></span></dt><dd><dl><dt><span class="section"><a href="containers.html#containers.sequences.list">list</a></span></dt><dt><span class="section"><a href="containers.html#containers.sequences.vector">vector</a></span></dt></dl></dd><dt><span class="section"><a href="associative.html">Associative</a></span></dt><dd><dl><dt><span class="section"><a href="associative.html#containers.associative.insert_hints">Insertion Hints</a></span></dt><dt><span class="section"><a href="associative.html#containers.associative.bitset">bitset</a></span></dt></dl></dd><dt><span class="section"><a href="containers_and_c.html">Interacting with C</a></span></dt><dd><dl><dt><span class="section"><a href="containers_and_c.html#containers.c.vs_array">Containers vs. Arrays</a></span></dt></dl></dd></dl></div><div class="section" title="Sequences"><div class="titlepage"><div><div><h2 class="title"><a id="std.containers.sequences"/>Sequences</h2></div></div></div><div class="section" title="list"><div class="titlepage"><div><div><h3 class="title"><a id="containers.sequences.list"/>list</h3></div></div></div><div class="section" title="list::size() is O(n)"><div class="titlepage"><div><div><h4 class="title"><a id="sequences.list.size"/>list::size() is O(n)</h4></div></div></div><p> + Yes it is, and that's okay. This is a decision that we preserved + when we imported SGI's STL implementation. The following is + quoted from <a class="link" href="http://www.sgi.com/tech/stl/FAQ.html">their FAQ</a>: + </p><div class="blockquote"><blockquote class="blockquote"><p> + The size() member function, for list and slist, takes time + proportional to the number of elements in the list. This was a + deliberate tradeoff. The only way to get a constant-time + size() for linked lists would be to maintain an extra member + variable containing the list's size. This would require taking + extra time to update that variable (it would make splice() a + linear time operation, for example), and it would also make the + list larger. Many list algorithms don't require that extra + word (algorithms that do require it might do better with + vectors than with lists), and, when it is necessary to maintain + an explicit size count, it's something that users can do + themselves. + </p><p> + This choice is permitted by the C++ standard. The standard says + that size() <span class="quote">“<span class="quote">should</span>”</span> be constant time, and + <span class="quote">“<span class="quote">should</span>”</span> does not mean the same thing as + <span class="quote">“<span class="quote">shall</span>”</span>. This is the officially recommended ISO + wording for saying that an implementation is supposed to do + something unless there is a good reason not to. + </p><p> + One implication of linear time size(): you should never write + </p><pre class="programlisting"> + if (L.size() == 0) + ... + </pre><p> + Instead, you should write + </p><pre class="programlisting"> + if (L.empty()) + ... + </pre></blockquote></div></div></div><div class="section" title="vector"><div class="titlepage"><div><div><h3 class="title"><a id="containers.sequences.vector"/>vector</h3></div></div></div><p> + </p><div class="section" title="Space Overhead Management"><div class="titlepage"><div><div><h4 class="title"><a id="sequences.vector.management"/>Space Overhead Management</h4></div></div></div><p> + In <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-04/msg00105.html">this + message to the list</a>, Daniel Kostecky announced work on an + alternate form of <code class="code">std::vector</code> that would support + hints on the number of elements to be over-allocated. The design + was also described, along with possible implementation choices. + </p><p> + The first two alpha releases were announced <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-07/msg00048.html">here</a> + and <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-07/msg00111.html">here</a>. + </p></div></div></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td align="left"><a accesskey="p" href="facets.html">Prev</a> </td><td align="center"><a accesskey="u" href="bk01pt02.html">Up</a></td><td align="right"> <a accesskey="n" href="associative.html">Next</a></td></tr><tr><td align="left" valign="top">Facets </td><td align="center"><a accesskey="h" href="../spine.html">Home</a></td><td align="right" valign="top"> Associative</td></tr></table></div></body></html> |