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| <a name="InputIterator"></a><div class="titlepage"></div> |
| <div class="refnamediv"> |
| <h2><span class="refentrytitle">Concept InputIterator</span></h2> |
| <p>InputIterator</p> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020735"></a><h2>Description</h2> |
| <p>An input iterator is an iterator that can read through a sequence of |
| values. It is single-pass (old values of the iterator cannot be |
| re-used), and read-only.</p> |
| <p>An input iterator represents a position in a sequence. Therefore, the |
| iterator can point into the sequence (returning a value when dereferenced |
| and being incrementable), or be off-the-end (and not dereferenceable or |
| incrementable).</p> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020753"></a><h2>Refinement of</h2> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"><p><a class="link" href="Assignable.html" title="Concept Assignable">Assignable</a></p></li> |
| <li class="listitem"><p><a class="link" href="DefaultConstructible.html" title="Concept DefaultConstructible">DefaultConstructible</a></p></li> |
| <li class="listitem"><p><a class="link" href="EqualityComparable.html" title="Concept EqualityComparable">EqualityComparable</a></p></li> |
| </ul></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020782"></a><h2>Associated types</h2> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| <p><span class="bold"><strong>value_type</strong></span></p> |
| <pre class="literallayout">std::iterator_traits<Iter>::value_type</pre> |
| <p>The value type of the iterator (not necessarily what |
| <code class="computeroutput">*i</code> returns)</p> |
| </li> |
| <li class="listitem"> |
| <p><span class="bold"><strong>difference_type</strong></span></p> |
| <pre class="literallayout">std::iterator_traits<Iter>::difference_type</pre> |
| <p>The difference type of the iterator</p> |
| </li> |
| <li class="listitem"> |
| <p><span class="bold"><strong>category</strong></span></p> |
| <pre class="literallayout">std::iterator_traits<Iter>::iterator_category</pre> |
| <p>The category of the iterator</p> |
| </li> |
| </ul></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020845"></a><h2>Notation</h2> |
| <div class="variablelist"><dl> |
| <dt><span class="term">Iter</span></dt> |
| <dd>A type playing the role of iterator-type in the <a class="link" href="InputIterator.html" title="Concept InputIterator">InputIterator</a> concept.</dd> |
| <dt> |
| <span class="term"><code class="varname">i</code>, </span><span class="term"><code class="varname">j</code></span> |
| </dt> |
| <dd>Objects of type Iter</dd> |
| <dt><span class="term"><code class="varname">x</code></span></dt> |
| <dd>Object of type value_type</dd> |
| </dl></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020884"></a><h2>Type expressions</h2> |
| <div class="variablelist"><dl> |
| <dt><span class="term">Category tag</span></dt> |
| <dd><p><span class="type">category</span> must be |
| derived from <span class="type">std::input_iterator_tag</span>, a model of <a class="link" href="DefaultConstructible.html" title="Concept DefaultConstructible">DefaultConstructible</a>, and a model of <a class="link" href="CopyConstructible.html" title="Concept CopyConstructible">CopyConstructible</a>. |
| </p></dd> |
| <dt><span class="term">Value type copy constructibility</span></dt> |
| <dd><p><span class="type">value_type</span> must be |
| a model of <a class="link" href="CopyConstructible.html" title="Concept CopyConstructible">CopyConstructible</a>. |
| </p></dd> |
| <dt><span class="term">Difference type properties</span></dt> |
| <dd><p><span class="type">difference_type</span> must be |
| a model of <a class="link" href="SignedInteger.html" title="Concept SignedInteger">SignedInteger</a>. |
| </p></dd> |
| </dl></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1020954"></a><h2>Valid expressions</h2> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th>Name</th> |
| <th>Expression</th> |
| <th>Type</th> |
| <th>Precondition</th> |
| <th>Semantics</th> |
| <th>Postcondition</th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td><p>Dereference</p></td> |
| <td><p>*i</p></td> |
| <td><p>Convertible to <span class="type">value_type</span></p></td> |
| <td><p><code class="computeroutput">i</code> is incrementable (not |
| off-the-end)</p></td> |
| <td> </td> |
| <td> </td> |
| </tr> |
| <tr> |
| <td><p>Preincrement</p></td> |
| <td><p>++i</p></td> |
| <td><p><span class="type">Iter &</span></p></td> |
| <td><p><code class="computeroutput">i</code> is incrementable (not |
| off-the-end)</p></td> |
| <td> </td> |
| <td> </td> |
| </tr> |
| <tr> |
| <td><p>Postincrement</p></td> |
| <td><p>i++</p></td> |
| <td><p></p></td> |
| <td><p><code class="computeroutput">i</code> is incrementable (not |
| off-the-end)</p></td> |
| <td><p>Equivalent to <code class="computeroutput">(void)(++i)</code></p></td> |
| <td><p><code class="computeroutput">i</code> is dereferenceable or |
| off-the-end</p></td> |
| </tr> |
| <tr> |
| <td><p>Postincrement and dereference</p></td> |
| <td><p>*i++</p></td> |
| <td><p>Convertible to <span class="type">value_type</span></p></td> |
| <td><p><code class="computeroutput">i</code> is incrementable (not |
| off-the-end)</p></td> |
| <td><p>Equivalent to <code class="computeroutput">{value_type t = *i; ++i; return t;}</code></p></td> |
| <td><p><code class="computeroutput">i</code> is dereferenceable or |
| off-the-end</p></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1021100"></a><h2>Complexity</h2> |
| <p> |
| All iterator operations must take amortized constant time. |
| </p> |
| </div> |
| <div class="refsect1"> |
| <a name="id1021106"></a><h2>Models</h2> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><span class="simplelist"><span class="type">std::istream_iterator</span></span></li></ul></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id1021119"></a><h2>See also</h2> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"><p><a class="link" href="DefaultConstructible.html" title="Concept DefaultConstructible">DefaultConstructible</a></p></li> |
| <li class="listitem"><p><a class="link" href="EqualityComparable.html" title="Concept EqualityComparable">EqualityComparable</a></p></li> |
| <li class="listitem"><p><a class="link" href="ForwardIterator.html" title="Concept ForwardIterator">ForwardIterator</a></p></li> |
| <li class="listitem"><p><a class="link" href="OutputIterator.html" title="Concept OutputIterator">OutputIterator</a></p></li> |
| </ul></div> |
| </div> |
| </div> |
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| <td align="right"><div class="copyright-footer">Copyright © 2001, 2002 Indiana University<br>Copyright © 2000, 2001 University of Notre Dame du Lac<br>Copyright © 2000 Jeremy Siek, Lie-Quan Lee, Andrew Lumsdaine<br>Copyright © 1996-1999 Silicon Graphics Computer Systems, Inc.<br>Copyright © 1994 Hewlett-Packard Company<p>Distributed under the Boost Software License, Version 1.0. |
| (See accompanying file <code class="filename">LICENSE_1_0.txt</code> or copy at |
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| <p>Some concepts based on versions from the MTL draft manual |
| and Boost Graph and Property Map documentation, the SGI Standard |
| Template Library documentation and the Hewlett-Packard STL, |
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