1169 lines
32 KiB
HTML
1169 lines
32 KiB
HTML
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"text/html; charset=us-ascii" />
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<title>Iterator Concepts</title>
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</head>
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<body>
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<h1><img src="../../../../boost.png" align="middle" />Iterator Concepts</h1>
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<div class="toc" id="toc"></div>
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<p>An Iterator is a restricted pointer-like object pointing into a
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vector or matrix container.</p>
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<h2><a name="indexed_bidirectional_iterator"
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></a>Indexed Bidirectional Iterator</h2>
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<h4>Description</h4>
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<p>An Indexed Bidirectional Iterator is an iterator of a container
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that can be dereferenced, incremented, decremented and carries
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index information.</p>
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<h4>Refinement of</h4>
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<p>Assignable, Equality Comparable, Default Constructible.</p>
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<h4>Associated types</h4>
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<table border="1" summary="associated types">
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<tbody>
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<tr>
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<td>Value type</td>
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<td>The type of the value obtained by dereferencing a Indexed
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Bidirectional Iterator</td>
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</tr>
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<tr>
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<td>Container type</td>
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<td>The type of the container a Indexed Bidirectional Iterator
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points into.</td>
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</tr>
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</tbody>
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</table>
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<h4>Notation</h4>
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<table border="0" summary="notation">
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<tbody>
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<tr>
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<td><code>I</code></td>
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<td>A type that is a model of Indexed Bidirectional Iterator</td>
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</tr>
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<tr>
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<td><code>T</code></td>
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<td>The value type of <code>I</code></td>
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</tr>
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<tr>
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<td><code>C</code></td>
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<td>The container type of <code>I</code></td>
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</tr>
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<tr>
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<td><code>it</code>, <code>itt, it1</code>, <code>it2</code></td>
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<td>Objects of type <code>I</code></td>
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</tr>
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<tr>
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<td><code>t</code></td>
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<td>Object of type <code>T</code></td>
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</tr>
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<tr>
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<td><code>c</code></td>
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<td>Object of type <code>C</code></td>
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</tr>
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</tbody>
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</table>
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<h4>Definitions</h4>
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<p>A Indexed Bidirectional Iterator may be <i>mutable</i>, meaning
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that the values referred to by objects of that type may be
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modified, or <i>constant</i> , meaning that they may not. If an
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iterator type is mutable, this implies that its value type is a
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model of Assignable; the converse, though, is not necessarily
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true.</p>
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<p>A Indexed Bidirectional Iterator may have a <i>singular</i>
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value, meaning that the results of most operations, including
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comparison for equality, are undefined. The only operation that is
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guaranteed to be supported is assigning a nonsingular iterator to a
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singular iterator.</p>
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<p>A Indexed Bidirectional Iterator may have a
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<i>dereferenceable</i> value, meaning that dereferencing it yields
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a well-defined value. Dereferenceable iterators are always
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nonsingular, but the converse is not true.</p>
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<p>An Indexed Bidirectional Iterator is <i>past-the-end</i> if it
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points beyond the last element of a container. Past-the-end values
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are nonsingular and nondereferenceable.</p>
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<h4>Valid expressions</h4>
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<p>In addition to the expressions defined for Assignable, Equality
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Comparable and Default Constructible, the following expressions
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must be valid.</p>
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<table border="1" summary="expressions">
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<tbody>
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<tr>
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<th>Name</th>
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<th>Expression</th>
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<th>Type requirements</th>
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<th>Return type</th>
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</tr>
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<tr>
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<td>Default constructor</td>
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<td><code>I it</code></td>
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<td> </td>
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<td> </td>
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</tr>
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<tr>
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<td>Dereference</td>
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<td><code>*it</code></td>
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<td> </td>
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<td>Convertible to <code>T</code>.</td>
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</tr>
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<tr>
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<td>Dereference assignment</td>
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<td><code>*it = t</code></td>
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<td><code>I</code> is mutable.</td>
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<td> </td>
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</tr>
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<tr>
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<td>Member access</td>
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<td><code>it->m</code></td>
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<td><code>T</code> is a type for which <code>t.m</code> is
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defined.</td>
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<td> </td>
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</tr>
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<tr>
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<td>Preincrement</td>
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<td><code>++ it</code></td>
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<td> </td>
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<td><code>I &</code></td>
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</tr>
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<tr>
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<td>Postincrement</td>
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<td><code>it ++</code></td>
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<td> </td>
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<td><code>I</code></td>
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</tr>
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<tr>
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<td>Predecrement</td>
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<td><code>-- it</code></td>
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<td> </td>
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<td><code>I &</code></td>
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</tr>
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<tr>
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<td>Postdecrement</td>
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<td><code>it --</code></td>
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<td> </td>
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<td><code>I</code></td>
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</tr>
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<tr>
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<td>Index</td>
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<td><code>it.index ()</code></td>
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<td> </td>
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<td><code>C::size_type</code></td>
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</tr>
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</tbody>
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</table>
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<h4>Expression Semantics</h4>
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<p>Semantics of an expression is defined only where it differs
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from, or is not defined in, Assignable, Equality Comparable and
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Default Constructible.</p>
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<table border="1" summary="semantics">
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<tbody>
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<tr>
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<th>Name</th>
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<th>Expression</th>
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<th>Precondition</th>
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<th>Semantics</th>
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<th>Postcondition</th>
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</tr>
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<tr>
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<td>Default constructor</td>
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<td><code>I it</code></td>
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<td> </td>
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<td> </td>
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<td><code>it</code> is singular.</td>
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</tr>
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<tr>
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<td>Dereference</td>
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<td><code>*it</code></td>
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<td><code>it</code> is dereferenceable.</td>
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<td> </td>
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<td> </td>
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</tr>
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<tr>
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<td>Dereference assignment</td>
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<td><code>*it = t</code></td>
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<td>Same as for <code>*it</code>.</td>
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<td> </td>
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<td><code>*it</code> is a copy of t.</td>
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</tr>
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<tr>
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<td>Member access</td>
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<td><code>it->m</code></td>
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<td><code>it</code> is dereferenceable.</td>
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<td>Equivalent to <code>(*it).m</code></td>
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<td> </td>
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</tr>
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<tr>
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<td>Preincrement</td>
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<td><code>++ it</code></td>
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<td><code>it</code> is dereferenceable.</td>
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<td><code>it</code> is modified to point to the next element.</td>
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<td><code>it</code> is dereferenceable or past-the-end.
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<code><br />
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&it == &++ it</code>.<br />
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If <code>it1 == it2</code>,<br />
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then <code>++ it1 == ++ it2</code>.</td>
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</tr>
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<tr>
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<td>Postincrement</td>
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<td><code>it ++</code></td>
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<td>Same as for <code>++ it</code>.</td>
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<td>Equivalent to<br />
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<code>{<br />
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I itt = it;<br />
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++ it;<br />
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return itt;<br />
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}</code></td>
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<td><code>it</code> is dereferenceable or past-the-end.</td>
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</tr>
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<tr>
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<td>Predecrement</td>
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<td><code>-- it</code></td>
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<td><code>it</code> is dereferenceable or past-the-end.<br />
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There exists a dereferenceable iterator <code>itt</code> such that
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<code>it == ++ itt</code>.</td>
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<td><code>it</code> is modified to point to the previous
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element.</td>
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<td><code>it</code> is dereferenceable.<br />
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<code>&it = &-- it</code>.<br />
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If <code>it1 == it2</code>,<br />
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then <code>-- it1 == -- it2</code>.<br />
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If <code>it2</code> is dereferenceable and <code>it1 ==
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++it2</code>,<br />
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then <code>--it1 == it2</code>.</td>
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</tr>
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<tr>
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<td>Postdecrement</td>
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<td><code>it --</code></td>
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<td>Same as for -- <code>it</code>.</td>
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<td>Equivalent to<br />
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<code>{<br />
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I itt = it;<br />
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-- it;<br />
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return itt;<br />
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}</code></td>
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<td><code>it</code> is dereferenceable. </td>
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</tr>
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<tr>
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<td>Index</td>
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<td><code>it.index ()</code></td>
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<td><code>it</code> is dereferenceable.</td>
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<td><code>it.index () >= 0</code><br />
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and<br />
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<code>it.index () < it ().size ()</code></td>
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<td>If <code>it1 == it2</code>,<br />
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then <code>it1.index () == it2.index ()</code>.<br />
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If <code>it1 == it2</code>,<br />
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then <code>it1.index () < (++ it2).index
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()</code>.<br />
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If <code>it1 == it2</code>,<br />
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then <code>it1.index () > (-- it2).index
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()</code>.</td>
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</tr>
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</tbody>
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</table>
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<h4>Complexity guarantees</h4>
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<p>The complexity of operations on indexed bidirectional iterators
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is guaranteed to be amortized constant time.</p>
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<h4>Invariants</h4>
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<table border="1" summary="invariants">
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<tbody>
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<tr>
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<td>Identity</td>
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<td><code>it1 == it2</code> if and only if <code>&*it1 ==
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&*it2</code>.</td>
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</tr>
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<tr>
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<td>Symmetry of increment and decrement</td>
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<td>If <code>it</code> is dereferenceable, then <code>++ it;
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--it;</code> is a null operation. Similarly, <code>-- it; ++
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it;</code> is a null operation.</td>
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</tr>
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<tr>
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<td>Relation between iterator index and container element
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operator</td>
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<td>If <code>it</code> is dereferenceable, <code>*it == it ()
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(it.index ())</code>.</td>
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</tr>
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</tbody>
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</table>
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<h4>Models</h4>
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<ul>
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<li><code>sparse_vector::iterator</code></li>
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</ul>
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<h2><a name="indexed_random_access_iterator"
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></a>Indexed Random Access Iterator</h2>
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<h4>Description</h4>
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<p>An Indexed Random Access Iterator is an iterator of a container
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that can be dereferenced, moved forward, moved backward and carries
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index information.</p>
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<h4>Refinement of</h4>
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<p>LessThanComparable, <a href=
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"#indexed_bidirectional_iterator">Indexed Bidirectional
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Iterator</a> .</p>
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<h4>Associated types</h4>
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<table border="1" summary="associated types">
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<tbody>
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<tr>
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<td>Value type</td>
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<td>The type of the value obtained by dereferencing a Indexed
|
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Random Access Iterator</td>
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</tr>
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<tr>
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<td>Container type</td>
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<td>The type of the container a Indexed Random Access Iterator
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points into.</td>
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</tr>
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</tbody>
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</table>
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<h4>Notation</h4>
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<table border="0" summary="notation">
|
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<tbody>
|
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<tr>
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<td><code>I</code></td>
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<td>A type that is a model of Indexed Random Access Iterator</td>
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</tr>
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<tr>
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<td><code>T</code></td>
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<td>The value type of <code>I</code></td>
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</tr>
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<tr>
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<td><code>C</code></td>
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<td>The container type of <code>I</code></td>
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</tr>
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<tr>
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<td><code>it</code>, <code>itt, it1</code>, <code>it2</code></td>
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<td>Objects of type <code>I</code></td>
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</tr>
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<tr>
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<td><code>t</code></td>
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<td>Object of type <code>T</code></td>
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</tr>
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<tr>
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<td><code>n</code></td>
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<td>Object of type <code>C::difference_type</code></td>
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</tr>
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</tbody>
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</table>
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<h4>Definitions</h4>
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<p>An Indexed Random Access Iterator <code>it1</code> is
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<i>reachable</i> from an Indexed Random Access Iterator
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<code>it2</code> if, after applying <code>operator ++</code> to
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<code>it2</code> a finite number of times, <code>it1 ==
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it2</code>.</p>
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<h4>Valid expressions</h4>
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<p>In addition to the expressions defined for <a href=
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"#indexed_bidirectional_iterator">Indexed Bidirectional
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Iterator</a> , the following expressions must be valid.</p>
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<table border="1" summary="expressions">
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<tbody>
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<tr>
|
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<th>Name</th>
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<th>Expression</th>
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<th>Type requirements</th>
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<th>Return type</th>
|
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</tr>
|
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<tr>
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<td>Forward motion</td>
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<td><code>it += n</code></td>
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<td> </td>
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<td><code>I &</code></td>
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</tr>
|
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<tr>
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<td>Iterator addition</td>
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<td><code>it + n</code></td>
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<td> </td>
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<td><code>I</code></td>
|
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</tr>
|
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<tr>
|
|
<td>Backward motion</td>
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<td><code>i -= n</code></td>
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<td> </td>
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<td><code>I &</code></td>
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</tr>
|
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<tr>
|
|
<td>Iterator subtraction</td>
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<td><code>it - n</code></td>
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<td> </td>
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<td><code>I</code> </td>
|
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</tr>
|
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<tr>
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|
<td>Difference</td>
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<td><code>it1 - it2</code></td>
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<td> </td>
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<td><code>C::difference_type</code></td>
|
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</tr>
|
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<tr>
|
|
<td>Element operator</td>
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<td><code>it [n]</code></td>
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<td> </td>
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<td>Convertible to <code>T</code>.</td>
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</tr>
|
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<tr>
|
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<td>Element assignment</td>
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<td><code>it [n] = t</code></td>
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<td><code>I</code> is mutable</td>
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<td>Convertible to <code>T</code>.</td>
|
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</tr>
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</tbody>
|
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</table>
|
|
<h4>Expression Semantics</h4>
|
|
<p>Semantics of an expression is defined only where it differs
|
|
from, or is not defined in, <a href=
|
|
"#indexed_bidirectional_iterator">Indexed Bidirectional
|
|
Iterator</a> .</p>
|
|
<table border="1" summary="semantics">
|
|
<tbody>
|
|
<tr>
|
|
<th>Name</th>
|
|
<th>Expression</th>
|
|
<th>Precondition</th>
|
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<th>Semantics</th>
|
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<th>Postcondition</th>
|
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</tr>
|
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<tr>
|
|
<td>Forward motion</td>
|
|
<td><code>it += n</code></td>
|
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<td>Including <code>it</code> itself, there must be <code>n</code>
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dereferenceable or past-the-end iterators following or preceding
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<code>it</code>, depending on whether <code>n</code> is positive or
|
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negative.</td>
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<td>If <code>n > 0</code>, equivalent to executing <code>++
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it</code> <code>n</code> times. If <code>n < 0</code>,
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equivalent to executing <code>-- it</code> <code>n</code> times. If
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<code>n == 0</code>, this is a null operation.</td>
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<td><code>it</code> is dereferenceable or past-the-end.</td>
|
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</tr>
|
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<tr>
|
|
<td>Iterator addition</td>
|
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<td><code>it + n</code></td>
|
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<td>Same as for <code>i += n</code>.</td>
|
|
<td>Equivalent to<br />
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|
<code>{<br />
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I itt = it;<br />
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return itt += n;<br />
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}</code></td>
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<td>Result is dereferenceable or past-the-end.</td>
|
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</tr>
|
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<tr>
|
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<td>Backward motion</td>
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<td><code>it -= n</code></td>
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<td>Including <code>it</code> itself, there must be <code>n</code>
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dereferenceable or past-the-end iterators preceding or following
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<code>it</code>, depending on whether <code>n</code> is positive or
|
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negative.</td>
|
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<td>Equivalent to <code>it += (-n)</code>.</td>
|
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<td><code>it</code> is dereferenceable or past-the-end.</td>
|
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</tr>
|
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<tr>
|
|
<td>Iterator subtraction</td>
|
|
<td><code>it - n</code></td>
|
|
<td>Same as for <code>i -= n</code>.</td>
|
|
<td>Equivalent to<br />
|
|
<code>{<br />
|
|
I itt = it;<br />
|
|
return itt -= n;<br />
|
|
}</code></td>
|
|
<td>Result is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Difference</td>
|
|
<td><code>it1 - it2</code></td>
|
|
<td>Either <code>it1</code> is reachable from <code>it2</code> or
|
|
<code>it2</code> is reachable from <code>it1</code>, or both.</td>
|
|
<td>Returns a number <code>n</code> such that <code>it1 == it2 +
|
|
n</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element operator</td>
|
|
<td><code>it [n]</code></td>
|
|
<td><code>it + n</code> exists and is dereferenceable.</td>
|
|
<td>Equivalent to <code>*(it + n)</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element assignment</td>
|
|
<td><code>i[n] = t</code></td>
|
|
<td>Same as for <code>it [n]</code>.</td>
|
|
<td>Equivalent to <code>*(it + n) = t</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Complexity guarantees</h4>
|
|
<p>The complexity of operations on indexed random access iterators
|
|
is guaranteed to be amortized constant time.</p>
|
|
<h4>Invariants</h4>
|
|
<table border="1" summary="invariants">
|
|
<tbody>
|
|
<tr>
|
|
<td>Symmetry of addition and subtraction</td>
|
|
<td>If <code>it + n</code> is well-defined, then <code>it += n; it
|
|
-= n;</code> and <code>(it + n) - n</code> are null operations.
|
|
Similarly, if <code>it - n</code> is well-defined, then <code>it -=
|
|
n; it += n;</code> and <code>(it - n) + n</code> are null
|
|
operations.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Relation between distance and addition</td>
|
|
<td>If <code>it1 - it2</code> is well-defined, then <code>it1 ==
|
|
it2 + (it1 - it2)</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reachability and distance</td>
|
|
<td>If <code>it1</code> is reachable from <code>it2</code>, then
|
|
<code>it1 - it2 >= 0</code>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Models</h4>
|
|
<ul>
|
|
<li><code>vector::iterator</code></li>
|
|
</ul>
|
|
<h2><a name="indexed_bidirectional_cr_iterator"
|
|
></a>Indexed Bidirectional Column/Row Iterator</h2>
|
|
<h4>Description</h4>
|
|
<p>An Indexed Bidirectional Column/Row Iterator is an iterator of a
|
|
container that can be dereferenced, incremented, decremented and
|
|
carries index information.</p>
|
|
<h4>Refinement of</h4>
|
|
<p>Assignable, Equality Comparable, Default Constructible.</p>
|
|
<h4>Associated types</h4>
|
|
<table border="1" summary="associated types">
|
|
<tbody>
|
|
<tr>
|
|
<td>Value type</td>
|
|
<td>The type of the value obtained by dereferencing a Indexed
|
|
Bidirectional Column/Row Iterator</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Container type</td>
|
|
<td>The type of the container a Indexed Bidirectional Column/Row
|
|
Iterator points into.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Notation</h4>
|
|
<table border="0" summary="notation">
|
|
<tbody>
|
|
<tr>
|
|
<td><code>I1</code></td>
|
|
<td>A type that is a model of Indexed Bidirectional Column/Row
|
|
Iterator</td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>I2</code></td>
|
|
<td>A type that is a model of Indexed Bidirectional Row/Column
|
|
Iterator</td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>T</code></td>
|
|
<td>The value type of <code>I1</code> and <code>I2</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>C</code></td>
|
|
<td>The container type of <code>I1</code> and <code>I2</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>it1</code>, <code>it1t, it11</code>,
|
|
<code>it12</code></td>
|
|
<td>Objects of type <code>I1</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>it2</code>, <code>it2t</code></td>
|
|
<td>Objects of type <code>I2</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>t</code></td>
|
|
<td>Object of type <code>T</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>c</code></td>
|
|
<td>Object of type <code>C</code></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Definitions</h4>
|
|
<h4>Valid expressions</h4>
|
|
<p>In addition to the expressions defined for Assignable, Equality
|
|
Comparable and Default Constructible, the following expressions
|
|
must be valid.</p>
|
|
<table border="1" summary="expressions">
|
|
<tbody>
|
|
<tr>
|
|
<th>Name</th>
|
|
<th>Expression</th>
|
|
<th>Type requirements</th>
|
|
<th>Return type</th>
|
|
</tr>
|
|
<tr>
|
|
<td>Default constructor</td>
|
|
<td><code>I1 it</code></td>
|
|
<td> </td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Dereference</td>
|
|
<td><code>*it</code></td>
|
|
<td> </td>
|
|
<td>Convertible to <code>T</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Dereference assignment</td>
|
|
<td><code>*it = t</code></td>
|
|
<td><code>I1</code> is mutable.</td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Member access</td>
|
|
<td><code>it->m</code></td>
|
|
<td><code>T</code> is a type for which <code>t.m</code> is
|
|
defined.</td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Preincrement</td>
|
|
<td><code>++ it</code></td>
|
|
<td> </td>
|
|
<td><code>I1 &</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Postincrement</td>
|
|
<td><code>it ++</code></td>
|
|
<td> </td>
|
|
<td><code>I1</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Predecrement</td>
|
|
<td><code>-- it</code></td>
|
|
<td> </td>
|
|
<td><code>I1 &</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Postdecrement</td>
|
|
<td><code>it --</code></td>
|
|
<td> </td>
|
|
<td><code>I1</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row Index</td>
|
|
<td><code>it.index1 ()</code></td>
|
|
<td> </td>
|
|
<td><code>C::size_type</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Column Index</td>
|
|
<td><code>it.index2 ()</code></td>
|
|
<td> </td>
|
|
<td><code>C::size_type</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row/Column Begin</td>
|
|
<td><code>it.begin ()</code></td>
|
|
<td> </td>
|
|
<td><code>I2</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row/Column End</td>
|
|
<td><code>it.end ()</code></td>
|
|
<td> </td>
|
|
<td><code>I2</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reverse Row/Column Begin</td>
|
|
<td><code>it.rbegin ()</code></td>
|
|
<td> </td>
|
|
<td><code>reverse_iterator<I2></code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reverse Row/Column End</td>
|
|
<td><code>it.rend ()</code></td>
|
|
<td> </td>
|
|
<td><code>reverse_iterator<I2></code></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Expression Semantics</h4>
|
|
<p>Semantics of an expression is defined only where it differs
|
|
from, or is not defined in, Assignable, Equality Comparable and
|
|
Default Constructible.</p>
|
|
<table border="1" summary="semantics">
|
|
<tbody>
|
|
<tr>
|
|
<th>Name</th>
|
|
<th>Expression</th>
|
|
<th>Precondition</th>
|
|
<th>Semantics</th>
|
|
<th>Postcondition</th>
|
|
</tr>
|
|
<tr>
|
|
<td>Default constructor</td>
|
|
<td><code>I1 it</code></td>
|
|
<td> </td>
|
|
<td> </td>
|
|
<td><code>it</code> is singular.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Dereference</td>
|
|
<td><code>*it</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td> </td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Dereference assignment</td>
|
|
<td><code>*it = t</code></td>
|
|
<td>Same as for <code>*it</code>.</td>
|
|
<td> </td>
|
|
<td><code>*it</code> is a copy of t.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Member access</td>
|
|
<td><code>it->m</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td>Equivalent to <code>(*it).m</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Preincrement</td>
|
|
<td><code>++ it</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td><code>it</code> is modified to point to the next element of
|
|
the column/row, i.e. for column iterators holds<br />
|
|
<code>it.index1 () < (++ it).index1 ()</code> and<br />
|
|
<code>it.index2 () == (++ it).index2 ()</code>,<br />
|
|
for row iterators holds<br />
|
|
<code>it.index1 () == (++ it).index1 ()</code> and<br />
|
|
<code>it.index2 () < (++ it).index2 ()</code>.<br /></td>
|
|
<td><code>it</code> is dereferenceable or past-the-end.
|
|
<code><br />
|
|
&it == &++ it</code>.<br />
|
|
If <code>it1 == it2</code>,<br />
|
|
then <code>++ it1 == ++ it2</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Postincrement</td>
|
|
<td><code>it ++</code></td>
|
|
<td>Same as for <code>++ it</code>.</td>
|
|
<td>Equivalent to<br />
|
|
<code>{<br />
|
|
I1 itt = it;<br />
|
|
++ it;<br />
|
|
return itt;<br />
|
|
}</code></td>
|
|
<td><code>it</code> is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Predecrement</td>
|
|
<td><code>-- it</code></td>
|
|
<td><code>it</code> is dereferenceable or past-the-end.<br />
|
|
There exists a dereferenceable iterator <code>itt</code> such that
|
|
<code>it == ++ itt</code>.</td>
|
|
<td><code>it</code> is modified to point to the previous
|
|
element of the column/row, i.e. for column iterators holds<br />
|
|
<code>it.index1 () > (-- it).index1 ()</code> and<br />
|
|
<code>it.index2 () == (-- it).index2 ()</code>,<br />
|
|
for row iterators holds<br />
|
|
<code>it.index1 () == (-- it).index1 ()</code> and<br />
|
|
<code>it.index2 () > (-- it).index2 ()</code>.</td>
|
|
<td><code>it</code> is dereferenceable.<br />
|
|
<code>&it = &-- it</code>.<br />
|
|
If <code>it1 == it2</code>,<br />
|
|
then <code>-- it1 == -- it2</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Postdecrement</td>
|
|
<td><code>it --</code></td>
|
|
<td>Same as for -- <code>it</code>.</td>
|
|
<td>Equivalent to<br />
|
|
<code>{<br />
|
|
I1 itt = it;<br />
|
|
-- it;<br />
|
|
return itt;<br />
|
|
}</code></td>
|
|
<td><code>it</code> is dereferenceable. </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row Index</td>
|
|
<td><code>it.index1 ()</code></td>
|
|
<td>If <code>it</code> is a Row iterator then <code>it</code> must be dereferenceable.</td>
|
|
<td><code>it.index1 () >= 0</code> and<br />
|
|
<code>it.index1 () < it () .size1 ()</code></td>
|
|
<td>If <code>it1 == it2</code>,<br />
|
|
then <code>it1.index1 () == 12.index1 ()</code>.<br />
|
|
If <code>it1</code>, <code>it2</code> are Row Iterators with <code>it1 == it2</code>,<br />
|
|
then <code>it1.index1 () < (++ it2</code>).<code>index1 ()</code>.<br />
|
|
and <code>it1.index1 () > (-- it2</code>).<code>index1 ()</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Column Index</td>
|
|
<td><code>it.index2 ()</code></td>
|
|
<td>If <code>it</code> is a Column iterator then <code>it</code> must be dereferenceable.</td>
|
|
<td><code>it.index2 () >= 0</code> and<br />
|
|
<code>it.index2 () < it () .size2 ()</code></td>
|
|
<td>If <code>it1 == it2</code>,<br />
|
|
then <code>it1.index2 () == it2</code>.<code>index2 ()</code>
|
|
.<br />
|
|
If <code>it1</code>, <code>it2</code> are Column Iterators with <code>it1 == i12</code>,<br />
|
|
then <code>it1.index2 () < (++ it2</code>).<code>index2 ()</code>.<br />
|
|
end <code>it1.index2 () > (-- it2</code>).<code>index2 ()</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row/Column Begin</td>
|
|
<td><code>it.begin ()</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td>If <code>it</code> is a Column Iterator,<br />
|
|
then <code>it2 = it.begin ()</code> is a Row Iterator<br />
|
|
with <code>it2.index1 () == it.index1 ()</code>.
|
|
<p>If <code>it</code> is a Row Iterator,<br />
|
|
then <code>it2 = it.begin ()</code> is a Column Iterator<br />
|
|
with <code>it2.index2 () == it.index2 ()</code>.</p>
|
|
</td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Row/Column End</td>
|
|
<td><code>it.end ()</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td>If <code>it</code> is a Column Iterator,<br />
|
|
then <code>it2 = it.end ()</code> is a Row Iterator<br />
|
|
with <code>it2.index1 () == it.index1 ()</code>.
|
|
<p>If <code>it</code> is a Row Iterator,<br />
|
|
then <code>it2 = it.end ()</code> is a Column Iterator<br />
|
|
with <code>it2.index2 () == it.index2 ()</code>.</p>
|
|
</td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reverse Row/Column Begin</td>
|
|
<td><code>it.rbegin ()</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td>Equivalent to <code>reverse_iterator<I2> (it.end
|
|
())</code>.</td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reverse Row/Column End</td>
|
|
<td><code>it.rend ()</code></td>
|
|
<td><code>it</code> is dereferenceable.</td>
|
|
<td>Equivalent to <code>reverse_iterator<I2> (it.begin
|
|
())</code>.</td>
|
|
<td> </td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Complexity guarantees</h4>
|
|
<p>The complexity of operations on indexed bidirectional column/row
|
|
iterators is guaranteed to be logarithmic depending on the size of
|
|
the container. The complexity of one iterator (depending on the
|
|
storage layout) can be lifted to be amortized constant time. The
|
|
complexity of the other iterator (depending on the storage layout
|
|
and the container) can be lifted to be amortized constant time for
|
|
the first row/first column respectively.</p>
|
|
<h4>Invariants</h4>
|
|
<table border="1" summary="invariants">
|
|
<tbody>
|
|
<tr>
|
|
<td>Identity</td>
|
|
<td><code>it1 == it2</code> if and only if <code>&*it1 ==
|
|
&*it2</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Symmetry of increment and decrement</td>
|
|
<td>If <code>it</code> is dereferenceable, then <code>++ it;
|
|
--it;</code> is a null operation. Similarly, <code>-- it; ++
|
|
it;</code> is a null operation.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Relation between iterator index and container element
|
|
operator</td>
|
|
<td>If <code>it</code> is dereferenceable, <code>*it == it ()
|
|
(it.index1 (), it.index2 ())</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Relation between iterator column/row begin and iterator
|
|
index</td>
|
|
<td>If <code>it</code> is a Column Iterator
|
|
and <code>it2 = it.begin ()</code> then <code>it2.index2 () <
|
|
it2t.index2 ()</code> for all <code>it2t</code> with <code>it2t ()
|
|
== it2 ()</code> and <code>it2t ().index1 () == it2 ().index1
|
|
()</code>.
|
|
<p>If <code>it</code> is a Row Iterator and
|
|
<code>it2 = it.begin ()</code> then <code>it2.index1 () <
|
|
it2t.index1 ()</code> for all <code>it2t</code> with <code>it2t ()
|
|
== it2 ()</code> and <code>it2t ().index2 () == it2 ().index2
|
|
()</code>.</p>
|
|
</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Relation between iterator column/row end and iterator
|
|
index</td>
|
|
<td>If <code>it</code> is a Column Iterator
|
|
and <code>it2 = it.end ()</code> then <code>it2.index2 () >
|
|
it2t.index2 ()</code> for all <code>it2t</code> with <code>it2t ()
|
|
== it2 ()</code> and <code>it2t ().index1 () == it2 ().index1
|
|
()</code>.
|
|
<p>If <code>it</code> is a Row Iterator and
|
|
<code>it2 = it.end ()</code> then <code>it2.index1 () >
|
|
it2t.index1 ()</code> for all <code>it2t</code> with <code>it2t ()
|
|
== it2 ()</code> and <code>it2t ().index2 () == it2 ().index2
|
|
()</code>.</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Models</h4>
|
|
<ul>
|
|
<li><code>sparse_matrix::iterator1</code></li>
|
|
<li><code>sparse_matrix::iterator2</code></li>
|
|
</ul>
|
|
<h2><a name="indexed_random_access_cr_iterator"
|
|
></a>Indexed Random Access Column/Row Iterator</h2>
|
|
<h4>Description</h4>
|
|
<p>An Indexed Random Access Column/Row Iterator is an iterator of a
|
|
container that can be dereferenced, incremented, decremented and
|
|
carries index information.</p>
|
|
<h4>Refinement of</h4>
|
|
<p><a href="#indexed_bidirectional_cr_iterator">Indexed
|
|
Bidirectional Column/Row Iterator</a> .</p>
|
|
<h4>Associated types</h4>
|
|
<table border="1" summary="associated types">
|
|
<tbody>
|
|
<tr>
|
|
<td>Value type</td>
|
|
<td>The type of the value obtained by dereferencing a Indexed
|
|
Random Access Column/Row Iterator</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Container type</td>
|
|
<td>The type of the container a Indexed Random Access Column/Row
|
|
Iterator points into.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Notation</h4>
|
|
<table border="0" summary="notation">
|
|
<tbody>
|
|
<tr>
|
|
<td><code>I</code></td>
|
|
<td>A type that is a model of Indexed Random Access Column/Row
|
|
Iterator</td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>T</code></td>
|
|
<td>The value type of <code>I</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>C</code></td>
|
|
<td>The container type of <code>I</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>it</code>, <code>itt, it1</code>, <code>it2</code></td>
|
|
<td>Objects of type <code>I</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>t</code></td>
|
|
<td>Object of type <code>T</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>c</code></td>
|
|
<td>Object of type <code>C</code></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Definitions</h4>
|
|
<h4>Valid expressions</h4>
|
|
<p>In addition to the expressions defined for <a href=
|
|
"#indexed_bidirectional_cr_iterator">Indexed Bidirectional
|
|
Column/Row Iterator</a> , the following expressions must be
|
|
valid.</p>
|
|
<table border="1" summary="expressions">
|
|
<tbody>
|
|
<tr>
|
|
<th>Name</th>
|
|
<th>Expression</th>
|
|
<th>Type requirements</th>
|
|
<th>Return type</th>
|
|
</tr>
|
|
<tr>
|
|
<td>Forward motion</td>
|
|
<td><code>it += n</code></td>
|
|
<td> </td>
|
|
<td><code>I &</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Iterator addition</td>
|
|
<td><code>it + n</code></td>
|
|
<td> </td>
|
|
<td><code>I</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Backward motion</td>
|
|
<td><code>i -= n</code></td>
|
|
<td> </td>
|
|
<td><code>I &</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Iterator subtraction</td>
|
|
<td><code>it - n</code></td>
|
|
<td> </td>
|
|
<td><code>I</code> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Difference</td>
|
|
<td><code>it1 - it2</code></td>
|
|
<td> </td>
|
|
<td><code>C::difference_type</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element operator</td>
|
|
<td><code>it [n]</code></td>
|
|
<td> </td>
|
|
<td>Convertible to <code>T</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element assignment</td>
|
|
<td><code>it [n] = t</code></td>
|
|
<td><code>I</code> is mutable</td>
|
|
<td>Convertible to <code>T</code>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Expression Semantics</h4>
|
|
<p>Semantics of an expression is defined only where it differs
|
|
from, or is not defined in, <a href=
|
|
"#indexed_bidirectional_cr_iterator">Indexed Bidirectional
|
|
Column/Row Iterator</a> .</p>
|
|
<table border="1" summary="semantics">
|
|
<tbody>
|
|
<tr>
|
|
<th>Name</th>
|
|
<th>Expression</th>
|
|
<th>Precondition</th>
|
|
<th>Semantics</th>
|
|
<th>Postcondition</th>
|
|
</tr>
|
|
<tr>
|
|
<td>Forward motion</td>
|
|
<td><code>it += n</code></td>
|
|
<td>Including <code>it</code> itself, there must be <code>n</code>
|
|
dereferenceable or past-the-end iterators following or preceding
|
|
<code>it</code>, depending on whether <code>n</code> is positive or
|
|
negative.</td>
|
|
<td>If <code>n > 0</code>, equivalent to executing <code>++
|
|
it</code> <code>n</code> times. If <code>n < 0</code>,
|
|
equivalent to executing <code>-- it</code> <code>n</code> times. If
|
|
<code>n == 0</code>, this is a null operation.</td>
|
|
<td><code>it</code> is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Iterator addition</td>
|
|
<td><code>it + n</code></td>
|
|
<td>Same as for <code>i += n</code>.</td>
|
|
<td>Equivalent to<br />
|
|
<code>{<br />
|
|
I itt = it;<br />
|
|
return itt += n;<br />
|
|
}</code></td>
|
|
<td>Result is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Backward motion</td>
|
|
<td><code>it -= n</code></td>
|
|
<td>Including <code>it</code> itself, there must be <code>n</code>
|
|
dereferenceable or past-the-end iterators preceding or following
|
|
<code>it</code>, depending on whether <code>n</code> is positive or
|
|
negative.</td>
|
|
<td>Equivalent to <code>it += (-n)</code>.</td>
|
|
<td><code>it</code> is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Iterator subtraction</td>
|
|
<td><code>it - n</code></td>
|
|
<td>Same as for <code>i -= n</code>.</td>
|
|
<td>Equivalent to<br />
|
|
<code>{<br />
|
|
I itt = it;<br />
|
|
return itt -= n;<br />
|
|
}</code></td>
|
|
<td>Result is dereferenceable or past-the-end.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Difference</td>
|
|
<td><code>it1 - it2</code></td>
|
|
<td>Either <code>it1</code> is reachable from <code>it2</code> or
|
|
<code>it2</code> is reachable from <code>it1</code>, or both.</td>
|
|
<td>Returns a number <code>n</code> such that <code>it1 == it2 +
|
|
n</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element operator</td>
|
|
<td><code>it [n]</code></td>
|
|
<td><code>it + n</code> exists and is dereferenceable.</td>
|
|
<td>Equivalent to <code>*(it + n)</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
<tr>
|
|
<td>Element assignment</td>
|
|
<td><code>i[n] = t</code></td>
|
|
<td>Same as for <code>it [n]</code>.</td>
|
|
<td>Equivalent to <code>*(it + n) = t</code></td>
|
|
<td> </td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Complexity guarantees</h4>
|
|
<p>The complexity of operations on indexed random access Column/Row
|
|
iterators is guaranteed to be amortized constant time.</p>
|
|
<h4>Invariants</h4>
|
|
<table border="1" summary="invariants">
|
|
<tbody>
|
|
<tr>
|
|
<td>Symmetry of addition and subtraction</td>
|
|
<td>If <code>it + n</code> is well-defined, then <code>it += n; it
|
|
-= n;</code> and <code>(it + n) - n</code> are null operations.
|
|
Similarly, if <code>it - n</code> is well-defined, then <code>it -=
|
|
n; it += n;</code> and <code>(it - n) + n</code> are null
|
|
operations.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Relation between distance and addition</td>
|
|
<td>If <code>it1 - it2</code> is well-defined, then <code>it1 ==
|
|
it2 + (it1 - it2)</code>.</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Reachability and distance</td>
|
|
<td>If <code>it1</code> is reachable from <code>it2</code>, then
|
|
<code>it1 - it2 >= 0</code>.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<h4>Models</h4>
|
|
<ul>
|
|
<li><code>matrix::iterator1</code></li>
|
|
<li><code>matrix::iterator2</code></li>
|
|
</ul>
|
|
<hr />
|
|
<p>Copyright (©) 2000-2002 Joerg Walter, Mathias Koch<br />
|
|
Use, modification and distribution are subject to the
|
|
Boost Software License, Version 1.0.
|
|
(See accompanying file LICENSE_1_0.txt
|
|
or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
|
|
http://www.boost.org/LICENSE_1_0.txt
|
|
</a>).
|
|
</p>
|
|
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