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<title>I/O</title>
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<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.sequences.operators.i_o"></a><a href="i_o.html" title="I/O">I/O</a></h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="i_o/in.html">in</a></span></dt>
<dt><span class="section"><a href="i_o/out.html">out</a></span></dt>
</dl></div>
<p>
The I/O operators: <tt class="computeroutput"><span class="special">&lt;&lt;</span></tt>
and <tt class="computeroutput"><span class="special">&gt;&gt;</span></tt> work generically
on all Fusion sequences. The global <tt class="computeroutput"><span class="keyword">operator</span><span class="special">&lt;&lt;</span></tt> has been overloaded for generic
output streams such that <span class="underline">_sequence</span>_s
are output by recursively calling <tt class="computeroutput"><span class="keyword">operator</span><span class="special">&lt;&lt;</span></tt> for each element. Analogously,
the global <tt class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></tt>
has been overloaded to extract <span class="underline">_sequence</span>_s
from generic input streams by recursively calling <tt class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></tt> for each element.
</p>
<p>
The default delimiter between the elements is space, and the <a href="../../sequences.html" title="Sequences">Sequence</a>
is enclosed in parenthesis. For Example:
</p>
<pre class="programlisting">
<a href="../containers/vector.html" title="vector"><tt class="computeroutput"><span class="identifier">vector</span></tt></a><span class="special">&lt;</span><span class="keyword">float</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&gt;</span> <span class="identifier">a</span><span class="special">(</span><span class="number">1.0f</span><span class="special">,</span> <span class="number">2</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"Howdy folks!"</span><span class="special">);</span>
<span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">a</span><span class="special">;</span>
</pre>
<p>
outputs the <a href="../containers/vector.html" title="vector"><tt class="computeroutput"><span class="identifier">vector</span></tt></a> as: (1.0 2 Howdy folks!)
</p>
<p>
The library defines three manipulators for changing the default behavior:
</p>
<div class="variablelist">
<p class="title"><b>Manipulators</b></p>
<dl>
<dt><span class="term"><tt class="computeroutput"><span class="identifier">tuple_open</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></tt></span></dt>
<dd>
Defines the character that is output before the first element.
</dd>
<dt><span class="term"><tt class="computeroutput"><span class="identifier">tuple_close</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></tt></span></dt>
<dd>
Defines the character that is output after the last element.
</dd>
<dt><span class="term"><tt class="computeroutput"><span class="identifier">tuple_delimiter</span><span class="special">(</span><span class="identifier">arg</span><span class="special">)</span></tt></span></dt>
<dd>
Defines the delimiter character between elements.
</dd>
</dl>
</div>
<p>
The argument to <tt class="computeroutput"><span class="identifier">tuple_open</span></tt>,
<tt class="computeroutput"><span class="identifier">tuple_close</span></tt> and <tt class="computeroutput"><span class="identifier">tuple_delimiter</span></tt> may be a <tt class="computeroutput"><span class="keyword">char</span></tt>, <tt class="computeroutput"><span class="keyword">wchar_t</span></tt>,
a C-string, or a wide C-string.
</p>
<p>
Example:
</p>
<pre class="programlisting">
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">tuple_delimiter</span><span class="special">(</span><span class="string">", "</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">a</span><span class="special">;</span>
</pre>
<p>
outputs the same <a href="../containers/vector.html" title="vector"><tt class="computeroutput"><span class="identifier">vector</span></tt></a>, <tt class="computeroutput"><span class="identifier">a</span></tt>
as: [1.0, 2, Howdy folks!]
</p>
<p>
The same manipulators work with <tt class="computeroutput"><span class="keyword">operator</span><span class="special">&gt;&gt;</span></tt> and <tt class="computeroutput"><span class="identifier">istream</span></tt>
as well. Suppose the <tt class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span></tt>
stream contains the following data:
</p>
<pre class="programlisting">
<span class="special">(</span><span class="number">1</span> <span class="number">2</span> <span class="number">3</span><span class="special">)</span> <span class="special">[</span><span class="number">4</span><span class="special">:</span><span class="number">5</span><span class="special">]</span>
</pre>
<p>
The code:
</p>
<pre class="programlisting">
<a href="../containers/vector.html" title="vector"><tt class="computeroutput"><span class="identifier">vector</span></tt></a><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">i</span><span class="special">;</span>
<a href="../containers/vector.html" title="vector"><tt class="computeroutput"><span class="identifier">vector</span></tt></a><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">j</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">i</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_open</span><span class="special">(</span><span class="char">'['</span><span class="special">)</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_close</span><span class="special">(</span><span class="char">']'</span><span class="special">)</span> <span class="special">&gt;&gt;</span> <span class="identifier">set_delimiter</span><span class="special">(</span><span class="char">':'</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cin</span> <span class="special">&gt;&gt;</span> <span class="identifier">j</span><span class="special">;</span>
</pre>
<p>
reads the data into the <span class="underline">_vector</span>_s
<tt class="computeroutput"><span class="identifier">i</span></tt> and <tt class="computeroutput"><span class="identifier">j</span></tt>.
</p>
<p>
Note that extracting <span class="underline">_sequence</span>_s
with <tt class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></tt> or C-style string elements does
not generally work, since the streamed <a href="../../sequences.html" title="Sequences">Sequence</a>
representation may not be unambiguously parseable.
</p>
<a name="fusion.sequences.operators.i_o.header"></a><h5>
<a name="id542372"></a>
<a href="i_o.html#fusion.sequences.operators.i_o.header">Header</a>
</h5>
<pre class="programlisting">
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">sequence</span><span class="special">/</span><span class="identifier">io</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
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