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<td align="right" valign="top" width="230"><a href="http://www.trolltech.com"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></a></td></tr></table><h1 align="center">QLinkedList::const_iterator Class Reference<br /><sup><sup>[<a href="qtcore.html">QtCore</a> module]</sup></sup></h1>
<p>The QLinkedList::const_iterator class provides an STL-style const iterator for <a href="qlinkedlist.html">QLinkedList</a>. <a href="#details">More...</a></p>
<pre> #include <<a href="qlinkedlist.html">QLinkedList</a>></pre><p>Inherited by <a href="q3valuelistconstiterator.html">Q3ValueListConstIterator</a>.</p>
<ul>
<li><a href="qlinkedlist-const-iterator-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-functions"></a>
<h3>Public Functions</h3>
<ul>
<li><div class="fn"/><b><a href="qlinkedlist-const-iterator.html#const_iterator">const_iterator</a></b> ()</li>
<li><div class="fn"/><b><a href="qlinkedlist-const-iterator.html#const_iterator-3">const_iterator</a></b> ( const const_iterator & <i>other</i> )</li>
<li><div class="fn"/><b><a href="qlinkedlist-const-iterator.html#const_iterator-4">const_iterator</a></b> ( iterator <i>other</i> )</li>
<li><div class="fn"/>bool <b><a href="qlinkedlist-const-iterator.html#operator-not-eq">operator!=</a></b> ( const const_iterator & <i>other</i> ) const</li>
<li><div class="fn"/>const T & <b><a href="qlinkedlist-const-iterator.html#operator-2a">operator*</a></b> () const</li>
<li><div class="fn"/>const_iterator <b><a href="qlinkedlist-const-iterator.html#operator-2b">operator+</a></b> ( int <i>j</i> ) const</li>
<li><div class="fn"/>const_iterator & <b><a href="qlinkedlist-const-iterator.html#operator-2b-2b">operator++</a></b> ()</li>
<li><div class="fn"/>const_iterator <b><a href="qlinkedlist-const-iterator.html#operator-2b-2b-2">operator++</a></b> ( int )</li>
<li><div class="fn"/>const_iterator & <b><a href="qlinkedlist-const-iterator.html#operator-2b-eq">operator+=</a></b> ( int <i>j</i> )</li>
<li><div class="fn"/>const_iterator <b><a href="qlinkedlist-const-iterator.html#operator-">operator-</a></b> ( int <i>j</i> ) const</li>
<li><div class="fn"/>const_iterator & <b><a href="qlinkedlist-const-iterator.html#operator--">operator--</a></b> ()</li>
<li><div class="fn"/>const_iterator <b><a href="qlinkedlist-const-iterator.html#operator---2">operator--</a></b> ( int )</li>
<li><div class="fn"/>const_iterator & <b><a href="qlinkedlist-const-iterator.html#operator--eq">operator-=</a></b> ( int <i>j</i> )</li>
<li><div class="fn"/>const T * <b><a href="qlinkedlist-const-iterator.html#operator--gt">operator-></a></b> () const</li>
<li><div class="fn"/>const_iterator & <b><a href="qlinkedlist-const-iterator.html#operator-eq">operator=</a></b> ( const const_iterator & <i>other</i> )</li>
<li><div class="fn"/>bool <b><a href="qlinkedlist-const-iterator.html#operator-eq-eq">operator==</a></b> ( const const_iterator & <i>other</i> ) const</li>
</ul>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QLinkedList::const_iterator class provides an STL-style const iterator for <a href="qlinkedlist.html">QLinkedList</a>.</p>
<p><a href="qlinkedlist.html">QLinkedList</a> features both <a href="containers.html#stl-style-iterators">STL-style iterators</a> and <a href="containers.html#java-style-iterators">Java-style iterators</a>. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity.</p>
<p><a href="qlinkedlist.html">QLinkedList</a><T>::const_iterator allows you to iterate over a <a href="qlinkedlist.html">QLinkedList</a><T>. If you want modify the <a href="qlinkedlist.html">QLinkedList</a> as you iterate over it, you must use QLinkedList::const_iterator instead. It is generally good practice to use QLinkedList::const_iterator on a non-const <a href="qlinkedlist.html">QLinkedList</a> as well, unless you need to change the <a href="qlinkedlist.html">QLinkedList</a> through the iterator. Const iterators are slightly faster, and can improve code readability.</p>
<p>The default QLinkedList::const_iterator constructor creates an uninitialized iterator. You must initialize it using a function like <a href="qlinkedlist.html#constBegin">QLinkedList::constBegin</a>(), <a href="qlinkedlist.html#constEnd">QLinkedList::constEnd</a>(), or <a href="qlinkedlist.html#insert">QLinkedList::insert</a>() before you can start iterating. Here's a typical loop that prints all the items stored in a list:</p>
<pre> QLinkedList<QString> list;
list.append("January");
list.append("February");
...
list.append("December");
QLinkedList<QString>::const_iterator i;
for (i = list.constBegin(); i != list.constEnd(); ++i)
cout << *i << endl;</pre>
<p>STL-style iterators can be used as arguments to <a href="qtalgorithms.html">generic algorithms</a>. For example, here's how to find an item in the list using the <a href="qtalgorithms.html#qFind">qFind</a>() algorithm:</p>
<pre> QLinkedList<QString> list;
...
QLinkedList<QString>::iterator it = qFind(list.constBegin(),
list.constEnd(), "Joel");
if (it != list.constEnd())
cout << "Found Joel" << endl;</pre>
<p>Multiple iterators can be used on the same list. If you add items to the list, existing iterators will remain valid. If you remove items from the list, iterators that point to the removed items will become dangling iterators.</p>
<p>See also <a href="qlinkedlist-iterator.html">QLinkedList::iterator</a> and <a href="qlinkedlistiterator.html">QLinkedListIterator</a>.</p>
<hr />
<h2>Member Function Documentation</h2>
<h3 class="fn"><a name="const_iterator"></a>const_iterator::const_iterator ()</h3>
<p>Constructs an uninitialized iterator.</p>
<p>Functions like operator*() and operator++() should not be called on an uninitialized iterartor. Use operator=() to assign a value to it before using it.</p>
<p>See also <a href="qlinkedlist.html#constBegin">QLinkedList::constBegin</a>() and <a href="qlinkedlist.html#constEnd">QLinkedList::constEnd</a>().</p>
<h3 class="fn"><a name="const_iterator-3"></a>const_iterator::const_iterator ( const const_iterator & <i>other</i> )</h3>
<p>Constructs a copy of <i>other</i>.</p>
<h3 class="fn"><a name="const_iterator-4"></a>const_iterator::const_iterator ( <a href="qlinkedlist-iterator.html">iterator</a> <i>other</i> )</h3>
<p>Constructs a copy of <i>other</i>.</p>
<h3 class="fn"><a name="operator-not-eq"></a>bool const_iterator::operator!= ( const const_iterator & <i>other</i> ) const</h3>
<p>Returns true if <i>other</i> points to a different item than this iterator; otherwise returns false.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-eq-eq">operator==</a>().</p>
<h3 class="fn"><a name="operator-2a"></a>const T & const_iterator::operator* () const</h3>
<p>Returns a reference to the current item.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator--gt">operator-></a>().</p>
<h3 class="fn"><a name="operator-2b"></a>const_iterator const_iterator::operator+ ( int <i>j</i> ) const</h3>
<p>Returns an iterator to the item at <i>j</i> positions forward from this iterator. (If <i>j</i> is negative, the iterator goes backward.)</p>
<p>This operation can be slow for large <i>j</i> values.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-">operator-</a>().</p>
<h3 class="fn"><a name="operator-2b-2b"></a>const_iterator & const_iterator::operator++ ()</h3>
<p>The prefix ++ operator (<tt>++it</tt>) advances the iterator to the next item in the list and returns an iterator to the new current item.</p>
<p>Calling this function on <a href="qlinkedlist.html#constEnd">QLinkedList::constEnd</a>() leads to undefined results.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator--">operator--</a>().</p>
<h3 class="fn"><a name="operator-2b-2b-2"></a>const_iterator const_iterator::operator++ ( int )</h3>
<p>This is an overloaded member function, provided for convenience.</p>
<p>The postfix ++ operator (<tt>it++</tt>) advances the iterator to the next item in the list and returns an iterator to the previously current item.</p>
<h3 class="fn"><a name="operator-2b-eq"></a>const_iterator & const_iterator::operator+= ( int <i>j</i> )</h3>
<p>Advances the iterator by <i>j</i> items. (If <i>j</i> is negative, the iterator goes backward.)</p>
<p>This operation can be slow for large <i>j</i> values.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator--eq">operator-=</a>() and <a href="qlinkedlist-const-iterator.html#operator-2b">operator+</a>().</p>
<h3 class="fn"><a name="operator-"></a>const_iterator const_iterator::operator- ( int <i>j</i> ) const</h3>
<p>This function returns an iterator to the item at <i>j</i> positions backward from this iterator. (If <i>j</i> is negative, the iterator goes forward.)</p>
<p>This operation can be slow for large <i>j</i> values.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-2b">operator+</a>().</p>
<h3 class="fn"><a name="operator--"></a>const_iterator & const_iterator::operator-- ()</h3>
<p>The prefix -- operator (<tt>--it</tt>) makes the preceding item current and returns an iterator to the new current item.</p>
<p>Calling this function on <a href="qlinkedlist.html#begin">QLinkedList::begin</a>() leads to undefined results.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-2b-2b">operator++</a>().</p>
<h3 class="fn"><a name="operator---2"></a>const_iterator const_iterator::operator-- ( int )</h3>
<p>This is an overloaded member function, provided for convenience.</p>
<p>The postfix -- operator (<tt>it--</tt>) makes the preceding item current and returns an iterator to the previously current item.</p>
<h3 class="fn"><a name="operator--eq"></a>const_iterator & const_iterator::operator-= ( int <i>j</i> )</h3>
<p>Makes the iterator go back by <i>j</i> items. (If <i>j</i> is negative, the iterator goes forward.)</p>
<p>This operation can be slow for large <i>j</i> values.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-2b-eq">operator+=</a>() and <a href="qlinkedlist-const-iterator.html#operator-">operator-</a>().</p>
<h3 class="fn"><a name="operator--gt"></a>const T * const_iterator::operator-> () const</h3>
<p>Returns a pointer to the current item.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-2a">operator*</a>().</p>
<h3 class="fn"><a name="operator-eq"></a>const_iterator & const_iterator::operator= ( const const_iterator & <i>other</i> )</h3>
<p>Assigns <i>other</i> to this iterator.</p>
<h3 class="fn"><a name="operator-eq-eq"></a>bool const_iterator::operator== ( const const_iterator & <i>other</i> ) const</h3>
<p>Returns true if <i>other</i> points to the same item as this iterator; otherwise returns false.</p>
<p>See also <a href="qlinkedlist-const-iterator.html#operator-not-eq">operator!=</a>().</p>
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