A Trivial Iterator <code>i</code> is a type that represents a reference to an element of some <ahref="./Sequence.html">Sequence</a>, and allows to access the element through its nested <code>type</code> member [<ahref="#1">1</a>]. A trivial iterator does not define any traversal operations.
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<h3>Definitions</h3>
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<ul>
<li>a trivial iterator can be <em>dereferenceable</em>, meaning that accessing its nested <code>type</code> member is a well-defined operation.
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<h3>Valid expressions</h3>
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<tableborder="1">
<tr><th> Expression </th><th> Expression type </th></tr>
<tr><td><code>typename i::type</code></td><td>A type </td></tr>
<tr><td><code>typename i::type</code></td><td>Amortized constant time</td><td><code>i</code> is dereferenceable</td><td><code>i::type</code> is identical to the type of the pointed element</td><td></td></tr>
</table>
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<h3>Invariants</h3>
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For any trivial iterators <code>i</code> and <code>j</code> the following invariants always hold:
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<ul>
<li><code>i</code> and <code>j</code> are identical if and only if they are pointing to the same element;
<li>if <code>i</code> is dereferenceable, and <code>j</code> is identical to <code>i</code>, then <code>j</code> is dereferenceable as well;
<li>if <code>i</code> and <code>j</code> are identical and dereferenceable, then <code>i::type</code> and <code>j::type</code> are identical.
</ul>
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<h3>Notes</h3>
[<aname="1">1</a>] Any trivial iterator is a model of [Nullary Metafunction Class] concept. <br>
