diff options
Diffstat (limited to 'gcc-4.8.1/libstdc++-v3/doc/html/manual/containers_and_c.html')
| -rw-r--r-- | gcc-4.8.1/libstdc++-v3/doc/html/manual/containers_and_c.html | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/gcc-4.8.1/libstdc++-v3/doc/html/manual/containers_and_c.html b/gcc-4.8.1/libstdc++-v3/doc/html/manual/containers_and_c.html deleted file mode 100644 index 2887ec268..000000000 --- a/gcc-4.8.1/libstdc++-v3/doc/html/manual/containers_and_c.html +++ /dev/null @@ -1,89 +0,0 @@ -<?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>Interacting with C</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.77.1" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="containers.html" title="Chapter 9. Containers" /><link rel="prev" href="unordered_associative.html" title="Unordered Associative" /><link rel="next" href="iterators.html" title="Chapter 10. Iterators" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Interacting with C</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="unordered_associative.html">Prev</a> </td><th width="60%" align="center">Chapter 9. - Containers - -</th><td width="20%" align="right"> <a accesskey="n" href="iterators.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.containers.c"></a>Interacting with C</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="containers.c.vs_array"></a>Containers vs. Arrays</h3></div></div></div><p> - You're writing some code and can't decide whether to use builtin - arrays or some kind of container. There are compelling reasons - to use one of the container classes, but you're afraid that - you'll eventually run into difficulties, change everything back - to arrays, and then have to change all the code that uses those - data types to keep up with the change. - </p><p> - If your code makes use of the standard algorithms, this isn't as - scary as it sounds. The algorithms don't know, nor care, about - the kind of <span class="quote">“<span class="quote">container</span>”</span> on which they work, since - the algorithms are only given endpoints to work with. For the - container classes, these are iterators (usually - <code class="code">begin()</code> and <code class="code">end()</code>, but not always). - For builtin arrays, these are the address of the first element - and the <a class="link" href="iterators.html#iterators.predefined.end" title="One Past the End">past-the-end</a> element. - </p><p> - Some very simple wrapper functions can hide all of that from the - rest of the code. For example, a pair of functions called - <code class="code">beginof</code> can be written, one that takes an array, - another that takes a vector. The first returns a pointer to the - first element, and the second returns the vector's - <code class="code">begin()</code> iterator. - </p><p> - The functions should be made template functions, and should also - be declared inline. As pointed out in the comments in the code - below, this can lead to <code class="code">beginof</code> being optimized out - of existence, so you pay absolutely nothing in terms of increased - code size or execution time. - </p><p> - The result is that if all your algorithm calls look like - </p><pre class="programlisting"> - std::transform(beginof(foo), endof(foo), beginof(foo), SomeFunction); - </pre><p> - then the type of foo can change from an array of ints to a vector - of ints to a deque of ints and back again, without ever changing - any client code. - </p><pre class="programlisting"> -// beginof -template<typename T> - inline typename vector<T>::iterator - beginof(vector<T> &v) - { return v.begin(); } - -template<typename T, unsigned int sz> - inline T* - beginof(T (&array)[sz]) { return array; } - -// endof -template<typename T> - inline typename vector<T>::iterator - endof(vector<T> &v) - { return v.end(); } - -template<typename T, unsigned int sz> - inline T* - endof(T (&array)[sz]) { return array + sz; } - -// lengthof -template<typename T> - inline typename vector<T>::size_type - lengthof(vector<T> &v) - { return v.size(); } - -template<typename T, unsigned int sz> - inline unsigned int - lengthof(T (&)[sz]) { return sz; } -</pre><p> - Astute readers will notice two things at once: first, that the - container class is still a <code class="code">vector<T></code> instead - of a more general <code class="code">Container<T></code>. This would - mean that three functions for <code class="code">deque</code> would have to be - added, another three for <code class="code">list</code>, and so on. This is - due to problems with getting template resolution correct; I find - it easier just to give the extra three lines and avoid confusion. - </p><p> - Second, the line - </p><pre class="programlisting"> - inline unsigned int lengthof (T (&)[sz]) { return sz; } - </pre><p> - looks just weird! Hint: unused parameters can be left nameless. - </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="unordered_associative.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="containers.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="iterators.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Unordered Associative </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 10. - Iterators - -</td></tr></table></div></body></html>
\ No newline at end of file |