boost_mpl/doc/refmanual/for-each.html

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<div class="section" id="for-each">
<h1><a class="toc-backref" href="./runtime-algorithms.html#id1509">for_each</a></h1>
<div class="section" id="id812">
<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3>
<pre class="literal-block">
template&lt;
      typename Sequence
    , typename F
    &gt;
void <a href="./for-each.html" class="identifier">for_each</a>( F f );

template&lt;
      typename Sequence
    , typename TransformOp
    , typename F
    &gt;
void <a href="./for-each.html" class="identifier">for_each</a>( F f );
</pre>
</div>
<div class="section" id="id813">
<h3><a class="subsection-title" href="#description" name="description">Description</a></h3>
<p><tt class="literal"><span class="pre"><a href="./for-each.html" class="identifier">for_each</a></span></tt> is a family of overloaded function templates:</p>
<ul class="simple">
<li><tt class="literal"><span class="pre"><a href="./for-each.html" class="identifier">for_each</a>&lt;Sequence&gt;(</span> <span class="pre">f</span> <span class="pre">)</span></tt> applies the runtime function object
<tt class="literal"><span class="pre">f</span></tt> to every element in the [<tt class="literal"><span class="pre"><a href="./begin.html" class="identifier">begin</a>&lt;Sequence&gt;::type</span></tt>, <tt class="literal"><span class="pre"><a href="./end.html" class="identifier">end</a>&lt;Sequence&gt;::type</span></tt>) range.</li>
<li><tt class="literal"><span class="pre"><a href="./for-each.html" class="identifier">for_each</a>&lt;Sequence,TransformOp&gt;(</span> <span class="pre">f</span> <span class="pre">)</span></tt> applies the runtime function
object <tt class="literal"><span class="pre">f</span></tt> to the result of the transformation <tt class="literal"><span class="pre">TransformOp</span></tt> of
every element in the [<tt class="literal"><span class="pre"><a href="./begin.html" class="identifier">begin</a>&lt;Sequence&gt;::type</span></tt>, <tt class="literal"><span class="pre"><a href="./end.html" class="identifier">end</a>&lt;Sequence&gt;::type</span></tt>) range.</li>
</ul>
</div>
<div class="section" id="id814">
<h3><a class="subsection-title" href="#header" name="header">Header</a></h3>
<pre class="literal-block">
#include &lt;<a href="../../../../boost/mpl/for_each.hpp" class="header">boost/mpl/for_each.hpp</a>&gt;
</pre>
</div>
<div class="section" id="id815">
<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3>
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<col width="39%" />
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<tr><th class="head">Parameter</th>
<th class="head">Requirement</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><tt class="literal"><span class="pre">Sequence</span></tt></td>
<td><a class="reference internal" href="./forward-sequence.html">Forward Sequence</a></td>
<td>A sequence to iterate.</td>
</tr>
<tr><td><tt class="literal"><span class="pre">TransformOp</span></tt></td>
<td><a class="reference internal" href="./lambda-expression.html">Lambda Expression</a></td>
<td>A transformation.</td>
</tr>
<tr><td><tt class="literal"><span class="pre">f</span></tt></td>
<td>An <a class="reference external" href="https://boost.org/sgi/stl/UnaryFunction.html" target="_top">unary function object</a></td>
<td>A runtime operation to apply.</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="id816">
<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3>
<p>For any <a class="reference internal" href="./forward-sequence.html">Forward Sequence</a> <tt class="literal"><span class="pre">s</span></tt>, <a class="reference internal" href="./lambda-expression.html">Lambda Expression</a> <tt class="literal"><span class="pre">op</span></tt> , and an
<a class="reference external" href="https://boost.org/sgi/stl/UnaryFunction.html" target="_top">unary function object</a> <tt class="literal"><span class="pre">f</span></tt>:</p>
<pre class="literal-block">
<a href="./for-each.html" class="identifier">for_each</a>&lt;s&gt;( f );
</pre>
<table class="docutils field-list" frame="void" rules="none">
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<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre">void</span></tt></p>
</td>
</tr>
<tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><p class="first">Equivalent to</p>
<pre class="literal-block">
typedef <a href="./begin.html" class="identifier">begin</a>&lt;Sequence&gt;::type i<sub>1</sub>;
<a class="reference external" href="http://www.boost.org/libs/utility/value_init.htm" target="_top">value_initialized</a>&lt; <a href="./deref.html" class="identifier">deref</a>&lt;i<sub>1</sub>&gt;::type &gt; x<sub>1</sub>;
f(boost::get(x<sub>1</sub>));

typedef <a href="./next.html" class="identifier">next</a>&lt;i<sub>1</sub>&gt;::type i<sub>2</sub>;
<a class="reference external" href="http://www.boost.org/libs/utility/value_init.htm" target="_top">value_initialized</a>&lt; <a href="./deref.html" class="identifier">deref</a>&lt;i<sub>2</sub>&gt;::type &gt; x<sub>2</sub>;
f(boost::get(x<sub>2</sub>));
<em>...</em>
<a class="reference external" href="http://www.boost.org/libs/utility/value_init.htm" target="_top">value_initialized</a>&lt; <a href="./deref.html" class="identifier">deref</a>&lt;i<sub>n</sub>&gt;::type &gt; x<sub>n</sub>;
f(boost::get(x<sub>n</sub>));
typedef <a href="./next.html" class="identifier">next</a>&lt;i<sub>n</sub>&gt;::type last;
</pre>
<p class="last">where <tt class="literal"><span class="pre">n</span> <span class="pre">==</span> <span class="pre"><a href="./size.html" class="identifier">size</a>&lt;s&gt;::value</span></tt> and <tt class="literal"><span class="pre">last</span></tt> is identical to
<tt class="literal"><span class="pre"><a href="./end.html" class="identifier">end</a>&lt;s&gt;::type</span></tt>; no effect if <tt class="literal"><span class="pre"><a href="./empty.html" class="identifier">empty</a>&lt;s&gt;::value</span> <span class="pre">==</span> <span class="pre">true</span></tt>.</p>
</td>
</tr>
</tbody>
</table>
<pre class="literal-block">
<a href="./for-each.html" class="identifier">for_each</a>&lt;s,op&gt;( f );
</pre>
<table class="docutils field-list" frame="void" rules="none">
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<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre">void</span></tt></p>
</td>
</tr>
<tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><p class="first">Equivalent to</p>
<pre class="last literal-block">
<a href="./for-each.html" class="identifier">for_each</a>&lt; <a href="./transform-view.html" class="identifier">transform_view</a>&lt;s,op&gt; &gt;( f );
</pre>
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</div>
<div class="section" id="id817">
<h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3>
<p>Linear. Exactly <tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a>&lt;s&gt;::value</span></tt> applications of <tt class="literal"><span class="pre">op</span></tt> and <tt class="literal"><span class="pre">f</span></tt>.</p>
</div>
<div class="section" id="id818">
<h3><a class="subsection-title" href="#example" name="example">Example</a></h3>
<pre class="literal-block">
struct value_printer
{
    template&lt; typename U &gt; void operator()(U x)
    {
        std::cout &lt;&lt; x &lt;&lt; '\n';
    }
};

int main()
{
    <a href="./for-each.html" class="identifier">for_each</a>&lt; <a href="./range-c.html" class="identifier">range_c</a>&lt;int,0,10&gt; &gt;( value_printer() );
}
</pre>
</div>
<div class="section" id="id819">
<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3>
<p><a class="reference internal" href="./runtime-algorithms.html">Runtime Algorithms</a>, <a class="reference internal" href="./views.html">Views</a>, <a class="reference internal" href="./transform-view.html">transform_view</a></p>
</div>
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