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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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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>Chapter 26. Memory Based Streams</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><meta name="keywords" content=" ISO C++ , library " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="io.html" title="Part XI. Input and Output" /><link rel="prev" href="bk01pt11ch25s02.html" title="Buffering" /><link rel="next" href="fstreams.html" title="Chapter 27. File Based Streams" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 26. Memory Based Streams</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="bk01pt11ch25s02.html">Prev</a> </td><th width="60%" align="center">Part XI.
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Input and Output
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</th><td width="20%" align="right"> <a accesskey="n" href="fstreams.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 26. Memory Based Streams"><div class="titlepage"><div><div><h2 class="title"><a id="manual.io.memstreams"></a>Chapter 26. Memory Based Streams</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="stringstreams.html#manual.io.memstreams.compat">Compatibility With strstream</a></span></dt></dl></div><div class="sect1" title="Compatibility With strstream"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.io.memstreams.compat"></a>Compatibility With strstream</h2></div></div></div><p>
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</p><p>Stringstreams (defined in the header <code class="code"><sstream></code>)
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are in this author's opinion one of the coolest things since
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sliced time. An example of their use is in the Received Wisdom
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section for Chapter 21 (Strings),
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<a class="link" href="bk01pt05ch13s06.html" title="CString (MFC)"> describing how to
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format strings</a>.
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</p><p>The quick definition is: they are siblings of ifstream and ofstream,
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and they do for <code class="code">std::string</code> what their siblings do for
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files. All that work you put into writing <code class="code"><<</code> and
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<code class="code">>></code> functions for your classes now pays off
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<span class="emphasis"><em>again!</em></span> Need to format a string before passing the string
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to a function? Send your stuff via <code class="code"><<</code> to an
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ostringstream. You've read a string as input and need to parse it?
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Initialize an istringstream with that string, and then pull pieces
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out of it with <code class="code">>></code>. Have a stringstream and need to
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get a copy of the string inside? Just call the <code class="code">str()</code>
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member function.
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</p><p>This only works if you've written your
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<code class="code"><<</code>/<code class="code">>></code> functions correctly, though,
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and correctly means that they take istreams and ostreams as
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parameters, not i<span class="emphasis"><em>f</em></span>streams and o<span class="emphasis"><em>f</em></span>streams. If they
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take the latter, then your I/O operators will work fine with
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file streams, but with nothing else -- including stringstreams.
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</p><p>If you are a user of the strstream classes, you need to update
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your code. You don't have to explicitly append <code class="code">ends</code> to
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terminate the C-style character array, you don't have to mess with
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"freezing" functions, and you don't have to manage the
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memory yourself. The strstreams have been officially deprecated,
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which means that 1) future revisions of the C++ Standard won't
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support them, and 2) if you use them, people will laugh at you.
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</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="bk01pt11ch25s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="io.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="fstreams.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Buffering </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 27. File Based Streams</td></tr></table></div></body></html>
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