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<title>Qt 4.8: QLinkedListIterator Class Reference</title>
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<a href="index.html" class="qtref"><span>Qt Reference Documentation</span></a>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QLinkedListIterator Class Reference</h1>
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<p>The QLinkedListIterator class provides a Java-style const iterator for <a href="qlinkedlist.html">QLinkedList</a>. <a href="#details">More...</a></p>
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<pre class="cpp"> <span class="preprocessor">#include <QLinkedListIterator></span></pre><ul>
<li><a href="qlinkedlistiterator-members.html">List of all members, including inherited members</a></li>
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<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#QLinkedListIterator">QLinkedListIterator</a></b> ( const QLinkedList<T> & <i>list</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#findNext">findNext</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#findPrevious">findPrevious</a></b> ( const T & <i>value</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#hasNext">hasNext</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#hasPrevious">hasPrevious</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const T & </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#next">next</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const T & </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#peekNext">peekNext</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const T & </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#peekPrevious">peekPrevious</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const T & </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#previous">previous</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#toBack">toBack</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#toFront">toFront</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QLinkedListIterator & </td><td class="memItemRight bottomAlign"><b><a href="qlinkedlistiterator.html#operator-eq">operator=</a></b> ( const QLinkedList<T> & <i>list</i> )</td></tr>
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<a name="details"></a>
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<div class="descr">
<h2>Detailed Description</h2>
<p>The QLinkedListIterator class provides a Java-style const iterator for <a href="qlinkedlist.html">QLinkedList</a>.</p>
<p><a href="qlinkedlist.html">QLinkedList</a> has both <a href="containers.html#java-style-iterators">Java-style iterators</a> and <a href="containers.html#stl-style-iterators">STL-style iterators</a>. The Java-style iterators are more high-level and easier to use than the STL-style iterators; on the other hand, they are slightly less efficient.</p>
<p>QLinkedListIterator<T> allows you to iterate over a <a href="qlinkedlist.html">QLinkedList</a><T>. If you want to modify the list as you iterate over it, use <a href="qmutablelinkedlistiterator.html">QMutableLinkedListIterator</a><T> instead.</p>
<p>The QLinkedListIterator constructor takes a <a href="qlinkedlist.html">QLinkedList</a> as argument. After construction, the iterator is located at the very beginning of the list (before the first item). Here's how to iterate over all the elements sequentially:</p>
<pre class="cpp"> <span class="type"><a href="qlinkedlist.html">QLinkedList</a></span><span class="operator"><</span><span class="type">float</span><span class="operator">></span> list;
<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>
<span class="type">QLinkedListIterator</span><span class="operator"><</span><span class="type">float</span><span class="operator">></span> i(list);
<span class="keyword">while</span> (i<span class="operator">.</span>hasNext())
<a href="qtglobal.html#qDebug">qDebug</a>() <span class="operator"><</span><span class="operator"><</span> i<span class="operator">.</span><a href="qlinkedlistiterator.html#next">next</a>();</pre>
<p>The <a href="qlinkedlistiterator.html#next">next</a>() function returns the next item in the list and advances the iterator. Unlike STL-style iterators, Java-style iterators point <i>between</i> items rather than directly <i>at</i> items. The first call to <a href="qlinkedlistiterator.html#next">next</a>() advances the iterator to the position between the first and second item, and returns the first item; the second call to <a href="qlinkedlistiterator.html#next">next</a>() advances the iterator to the position between the second and third item, and returns the second item; and so on.</p>
<p class="centerAlign"><img src="images/javaiterators1.png" alt="" /></p><p>Here's how to iterate over the elements in reverse order:</p>
<pre class="cpp"> <span class="type">QLinkedListIterator</span><span class="operator"><</span><span class="type">float</span><span class="operator">></span> i(list);
i<span class="operator">.</span><a href="qlinkedlistiterator.html#toBack">toBack</a>();
<span class="keyword">while</span> (i<span class="operator">.</span>hasPrevious())
<a href="qtglobal.html#qDebug">qDebug</a>() <span class="operator"><</span><span class="operator"><</span> i<span class="operator">.</span><a href="qlinkedlistiterator.html#previous">previous</a>();</pre>
<p>If you want to find all occurrences of a particular value, use <a href="qlinkedlistiterator.html#findNext">findNext</a>() or <a href="qlinkedlistiterator.html#findPrevious">findPrevious</a>() in a loop.</p>
<p>Multiple iterators can be used on the same list. If the list is modified while a QLinkedListIterator is active, the QLinkedListIterator will continue iterating over the original list, ignoring the modified copy.</p>
</div>
<p><b>See also </b><a href="qmutablelinkedlistiterator.html">QMutableLinkedListIterator</a> and <a href="qlinkedlist-const-iterator.html">QLinkedList::const_iterator</a>.</p>
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<div class="func">
<h2>Member Function Documentation</h2>
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<h3 class="fn"><a name="QLinkedListIterator"></a>QLinkedListIterator::<span class="name">QLinkedListIterator</span> ( const <span class="type"><a href="qlinkedlist.html">QLinkedList</a></span><<span class="type">T</span>> & <i>list</i> )</h3>
<p>Constructs an iterator for traversing <i>list</i>. The iterator is set to be at the front of the list (before the first item).</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#operator-eq">operator=</a>().</p>
<!-- @@@QLinkedListIterator -->
<!-- $$$findNext[overload1]$$$findNextconstT& -->
<h3 class="fn"><a name="findNext"></a><span class="type">bool</span> QLinkedListIterator::<span class="name">findNext</span> ( const <span class="type">T</span> & <i>value</i> )</h3>
<p>Searches for <i>value</i> starting from the current iterator position forward. Returns true if <i>value</i> is found; otherwise returns false.</p>
<p>After the call, if <i>value</i> was found, the iterator is positioned just after the matching item; otherwise, the iterator is positioned at the back of the container.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#findPrevious">findPrevious</a>().</p>
<!-- @@@findNext -->
<!-- $$$findPrevious[overload1]$$$findPreviousconstT& -->
<h3 class="fn"><a name="findPrevious"></a><span class="type">bool</span> QLinkedListIterator::<span class="name">findPrevious</span> ( const <span class="type">T</span> & <i>value</i> )</h3>
<p>Searches for <i>value</i> starting from the current iterator position backward. Returns true if <i>value</i> is found; otherwise returns false.</p>
<p>After the call, if <i>value</i> was found, the iterator is positioned just before the matching item; otherwise, the iterator is positioned at the front of the container.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#findNext">findNext</a>().</p>
<!-- @@@findPrevious -->
<!-- $$$hasNext[overload1]$$$hasNext -->
<h3 class="fn"><a name="hasNext"></a><span class="type">bool</span> QLinkedListIterator::<span class="name">hasNext</span> () const</h3>
<p>Returns true if there is at least one item ahead of the iterator, i.e. the iterator is <i>not</i> at the back of the container; otherwise returns false.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasPrevious">hasPrevious</a>() and <a href="qlinkedlistiterator.html#next">next</a>().</p>
<!-- @@@hasNext -->
<!-- $$$hasPrevious[overload1]$$$hasPrevious -->
<h3 class="fn"><a name="hasPrevious"></a><span class="type">bool</span> QLinkedListIterator::<span class="name">hasPrevious</span> () const</h3>
<p>Returns true if there is at least one item behind the iterator, i.e. the iterator is <i>not</i> at the front of the container; otherwise returns false.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasNext">hasNext</a>() and <a href="qlinkedlistiterator.html#previous">previous</a>().</p>
<!-- @@@hasPrevious -->
<!-- $$$next[overload1]$$$next -->
<h3 class="fn"><a name="next"></a>const <span class="type">T</span> & QLinkedListIterator::<span class="name">next</span> ()</h3>
<p>Returns the next item and advances the iterator by one position.</p>
<p>Calling this function on an iterator located at the back of the container leads to undefined results.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasNext">hasNext</a>(), <a href="qlinkedlistiterator.html#peekNext">peekNext</a>(), and <a href="qlinkedlistiterator.html#previous">previous</a>().</p>
<!-- @@@next -->
<!-- $$$peekNext[overload1]$$$peekNext -->
<h3 class="fn"><a name="peekNext"></a>const <span class="type">T</span> & QLinkedListIterator::<span class="name">peekNext</span> () const</h3>
<p>Returns the next item without moving the iterator.</p>
<p>Calling this function on an iterator located at the back of the container leads to undefined results.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasNext">hasNext</a>(), <a href="qlinkedlistiterator.html#next">next</a>(), and <a href="qlinkedlistiterator.html#peekPrevious">peekPrevious</a>().</p>
<!-- @@@peekNext -->
<!-- $$$peekPrevious[overload1]$$$peekPrevious -->
<h3 class="fn"><a name="peekPrevious"></a>const <span class="type">T</span> & QLinkedListIterator::<span class="name">peekPrevious</span> () const</h3>
<p>Returns the previous item without moving the iterator.</p>
<p>Calling this function on an iterator located at the front of the container leads to undefined results.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasPrevious">hasPrevious</a>(), <a href="qlinkedlistiterator.html#previous">previous</a>(), and <a href="qlinkedlistiterator.html#peekNext">peekNext</a>().</p>
<!-- @@@peekPrevious -->
<!-- $$$previous[overload1]$$$previous -->
<h3 class="fn"><a name="previous"></a>const <span class="type">T</span> & QLinkedListIterator::<span class="name">previous</span> ()</h3>
<p>Returns the previous item and moves the iterator back by one position.</p>
<p>Calling this function on an iterator located at the front of the container leads to undefined results.</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#hasPrevious">hasPrevious</a>(), <a href="qlinkedlistiterator.html#peekPrevious">peekPrevious</a>(), and <a href="qlinkedlistiterator.html#next">next</a>().</p>
<!-- @@@previous -->
<!-- $$$toBack[overload1]$$$toBack -->
<h3 class="fn"><a name="toBack"></a><span class="type">void</span> QLinkedListIterator::<span class="name">toBack</span> ()</h3>
<p>Moves the iterator to the back of the container (after the last item).</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#toFront">toFront</a>() and <a href="qlinkedlistiterator.html#previous">previous</a>().</p>
<!-- @@@toBack -->
<!-- $$$toFront[overload1]$$$toFront -->
<h3 class="fn"><a name="toFront"></a><span class="type">void</span> QLinkedListIterator::<span class="name">toFront</span> ()</h3>
<p>Moves the iterator to the front of the container (before the first item).</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#toBack">toBack</a>() and <a href="qlinkedlistiterator.html#next">next</a>().</p>
<!-- @@@toFront -->
<!-- $$$operator=[overload1]$$$operator=constQLinkedList<T>& -->
<h3 class="fn"><a name="operator-eq"></a><span class="type">QLinkedListIterator</span> & QLinkedListIterator::<span class="name">operator=</span> ( const <span class="type"><a href="qlinkedlist.html">QLinkedList</a></span><<span class="type">T</span>> & <i>list</i> )</h3>
<p>Makes the iterator operate on <i>list</i>. The iterator is set to be at the front of the list (before the first item).</p>
<p><b>See also </b><a href="qlinkedlistiterator.html#toFront">toFront</a>() and <a href="qlinkedlistiterator.html#toBack">toBack</a>().</p>
<!-- @@@operator= -->
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