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<td ><a href="../qtdoc/index.html">Qt 5.11</a></td><td ><a href="qtcore-index.html">Qt Core</a></td><td ><a href="qtcore-module.html">C++ Classes</a></td><td >QStack</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.11.2 Reference Documentation</td>
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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">QStack Class</h1>
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<p>The <a href="qstack.html">QStack</a> class is a template class that provides a stack. <a href="#details">More...</a></p>
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<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign">   <span class="preprocessor">#include &lt;QStack&gt;</span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += core</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="qvector.html">QVector</a></td></tr></table></div><ul>
<li><a href="qstack-members.html">List of all members, including inherited members</a></li>
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<p><b>Note:</b> All functions in this class are <a href="../qtdoc/threads-reentrancy.html">reentrant</a>.</p>
<a name="public-functions"></a>
<h2 id="public-functions">Public Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> T </td><td class="memItemRight bottomAlign"><b><a href="qstack.html#pop">pop</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qstack.html#push">push</a></b>(const T &amp;<i>t</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qstack.html#swap">swap</a></b>(QStack&lt;T&gt; &amp;<i>other</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> T &amp;</td><td class="memItemRight bottomAlign"><b><a href="qstack.html#top">top</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const T &amp;</td><td class="memItemRight bottomAlign"><b><a href="qstack.html#top-1">top</a></b>() const</td></tr>
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<li class="fn">96 public functions inherited from <a href="qvector.html#public-functions">QVector</a></li>
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<h3>Additional Inherited Members</h3>
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<li class="fn">2 static public members inherited from <a href="qvector.html#static-public-members">QVector</a></li>
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<a name="details"></a>
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<h2 id="details">Detailed Description</h2>
<p>The <a href="qstack.html">QStack</a> class is a template class that provides a stack.</p>
<p><a href="qstack.html">QStack</a>&lt;T&gt; is one of Qt's generic <a href="containers.html">container classes</a>. It implements a stack data structure for items of a same type.</p>
<p>A stack is a last in, first out (LIFO) structure. Items are added to the top of the stack using <a href="qstack.html#push">push</a>() and retrieved from the top using <a href="qstack.html#pop">pop</a>(). The <a href="qstack.html#top">top</a>() function provides access to the topmost item without removing it.</p>
<p>Example:</p>
<pre class="cpp">

      <span class="type"><a href="qstack.html">QStack</a></span><span class="operator">&lt;</span><span class="type">int</span><span class="operator">&gt;</span> stack;
      stack<span class="operator">.</span>push(<span class="number">1</span>);
      stack<span class="operator">.</span>push(<span class="number">2</span>);
      stack<span class="operator">.</span>push(<span class="number">3</span>);
      <span class="keyword">while</span> (<span class="operator">!</span>stack<span class="operator">.</span>isEmpty())
          cout <span class="operator">&lt;</span><span class="operator">&lt;</span> stack<span class="operator">.</span>pop() <span class="operator">&lt;</span><span class="operator">&lt;</span> endl;

</pre>
<p>The example will output 3, 2, 1 in that order.</p>
<p><a href="qstack.html">QStack</a> inherits from <a href="qvector.html">QVector</a>. All of <a href="qvector.html">QVector</a>'s functionality also applies to <a href="qstack.html">QStack</a>. For example, you can use <a href="qvector.html#isEmpty">isEmpty</a>() to test whether the stack is empty, and you can traverse a <a href="qstack.html">QStack</a> using <a href="qvector.html">QVector</a>'s iterator classes (for example, <a href="qvectoriterator.html">QVectorIterator</a>). But in addition, <a href="qstack.html">QStack</a> provides three convenience functions that make it easy to implement LIFO semantics: <a href="qstack.html#push">push</a>(), <a href="qstack.html#pop">pop</a>(), and <a href="qstack.html#top">top</a>().</p>
<p><a href="qstack.html">QStack</a>'s value type must be an <a href="containers.html#assignable-data-type">assignable data type</a>. This covers most data types that are commonly used, but the compiler won't let you, for example, store a <a href="../qtwidgets/qwidget.html">QWidget</a> as a value; instead, store a <a href="../qtwidgets/qwidget.html">QWidget</a> *.</p>
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<p><b>See also </b><a href="qvector.html">QVector</a> and <a href="qqueue.html">QQueue</a>.</p>
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<h2>Member Function Documentation</h2>
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<h3 class="fn" id="pop"><a name="pop"></a><span class="type">T</span> QStack::<span class="name">pop</span>()</h3>
<p>Removes the top item from the stack and returns it. This function assumes that the stack isn't empty.</p>
<p><b>See also </b><a href="qstack.html#top">top</a>(), <a href="qstack.html#push">push</a>(), and <a href="qvector.html#isEmpty">isEmpty</a>().</p>
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<h3 class="fn" id="push"><a name="push"></a><span class="type">void</span> QStack::<span class="name">push</span>(const <span class="type">T</span> &amp;<i>t</i>)</h3>
<p>Adds element <i>t</i> to the top of the stack.</p>
<p>This is the same as <a href="qvector.html#append">QVector::append</a>().</p>
<p><b>See also </b><a href="qstack.html#pop">pop</a>() and <a href="qstack.html#top">top</a>().</p>
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<h3 class="fn" id="swap"><a name="swap"></a><span class="type">void</span> QStack::<span class="name">swap</span>(<span class="type"><a href="qstack.html">QStack</a></span>&lt;<span class="type">T</span>&gt; &amp;<i>other</i>)</h3>
<p>Swaps stack <i>other</i> with this stack. This operation is very fast and never fails.</p>
<p>This function was introduced in  Qt 4.8.</p>
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<h3 class="fn" id="top"><a name="top"></a><span class="type">T</span> &amp;QStack::<span class="name">top</span>()</h3>
<p>Returns a reference to the stack's top item. This function assumes that the stack isn't empty.</p>
<p>This is the same as <a href="qvector.html#last">QVector::last</a>().</p>
<p><b>See also </b><a href="qstack.html#pop">pop</a>(), <a href="qstack.html#push">push</a>(), and <a href="qvector.html#isEmpty">isEmpty</a>().</p>
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<h3 class="fn" id="top-1"><a name="top-1"></a>const <span class="type">T</span> &amp;QStack::<span class="name">top</span>() const</h3>
<p>This is an overloaded function.</p>
<p><b>See also </b><a href="qstack.html#pop">pop</a>() and <a href="qstack.html#push">push</a>().</p>
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