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qt4-x11/doc/html/widgets-calculator-calculator-cpp.html
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<h1 class="title">calculator.cpp Example File</h1>
<span class="small-subtitle">widgets/calculator/calculator.cpp</span>
<!-- $$$widgets/calculator/calculator.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** &quot;Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
**
** $QT_END_LICENSE$
**
****************************************************************************/</span>
<span class="preprocessor">#include &lt;QtGui&gt;</span>
<span class="preprocessor">#include &lt;math.h&gt;</span>
<span class="preprocessor">#include &quot;button.h&quot;</span>
<span class="preprocessor">#include &quot;calculator.h&quot;</span>
Calculator<span class="operator">::</span>Calculator(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent)
: <span class="type"><a href="qwidget.html">QWidget</a></span>(parent)
{
sumInMemory <span class="operator">=</span> <span class="number">0.0</span>;
sumSoFar <span class="operator">=</span> <span class="number">0.0</span>;
factorSoFar <span class="operator">=</span> <span class="number">0.0</span>;
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
display <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qlineedit.html">QLineEdit</a></span>(<span class="string">&quot;0&quot;</span>);
display<span class="operator">-</span><span class="operator">&gt;</span>setReadOnly(<span class="keyword">true</span>);
display<span class="operator">-</span><span class="operator">&gt;</span>setAlignment(<span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>AlignRight);
display<span class="operator">-</span><span class="operator">&gt;</span>setMaxLength(<span class="number">15</span>);
<span class="type"><a href="qfont.html">QFont</a></span> font <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>font();
font<span class="operator">.</span>setPointSize(font<span class="operator">.</span>pointSize() <span class="operator">+</span> <span class="number">8</span>);
display<span class="operator">-</span><span class="operator">&gt;</span>setFont(font);
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator">&lt;</span> NumDigitButtons; <span class="operator">+</span><span class="operator">+</span>i) {
digitButtons<span class="operator">[</span>i<span class="operator">]</span> <span class="operator">=</span> createButton(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(i)<span class="operator">,</span> SLOT(digitClicked()));
}
Button <span class="operator">*</span>pointButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;.&quot;</span>)<span class="operator">,</span> SLOT(pointClicked()));
Button <span class="operator">*</span>changeSignButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;\261&quot;</span>)<span class="operator">,</span> SLOT(changeSignClicked()));
Button <span class="operator">*</span>backspaceButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;Backspace&quot;</span>)<span class="operator">,</span> SLOT(backspaceClicked()));
Button <span class="operator">*</span>clearButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;Clear&quot;</span>)<span class="operator">,</span> SLOT(clear()));
Button <span class="operator">*</span>clearAllButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;Clear All&quot;</span>)<span class="operator">,</span> SLOT(clearAll()));
Button <span class="operator">*</span>clearMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;MC&quot;</span>)<span class="operator">,</span> SLOT(clearMemory()));
Button <span class="operator">*</span>readMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;MR&quot;</span>)<span class="operator">,</span> SLOT(readMemory()));
Button <span class="operator">*</span>setMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;MS&quot;</span>)<span class="operator">,</span> SLOT(setMemory()));
Button <span class="operator">*</span>addToMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;M+&quot;</span>)<span class="operator">,</span> SLOT(addToMemory()));
Button <span class="operator">*</span>divisionButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;\367&quot;</span>)<span class="operator">,</span> SLOT(multiplicativeOperatorClicked()));
Button <span class="operator">*</span>timesButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;\327&quot;</span>)<span class="operator">,</span> SLOT(multiplicativeOperatorClicked()));
Button <span class="operator">*</span>minusButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;-&quot;</span>)<span class="operator">,</span> SLOT(additiveOperatorClicked()));
Button <span class="operator">*</span>plusButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;+&quot;</span>)<span class="operator">,</span> SLOT(additiveOperatorClicked()));
Button <span class="operator">*</span>squareRootButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;Sqrt&quot;</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked()));
Button <span class="operator">*</span>powerButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;x\262&quot;</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked()));
Button <span class="operator">*</span>reciprocalButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;1/x&quot;</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked()));
Button <span class="operator">*</span>equalButton <span class="operator">=</span> createButton(tr(<span class="string">&quot;=&quot;</span>)<span class="operator">,</span> SLOT(equalClicked()));
<span class="type"><a href="qgridlayout.html">QGridLayout</a></span> <span class="operator">*</span>mainLayout <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qgridlayout.html">QGridLayout</a></span>;
<span class="preprocessor">#if defined(Q_OS_SYMBIAN) || defined(Q_WS_MAEMO_5) || defined(Q_WS_SIMULATOR)</span>
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>setSizeConstraint(<span class="type"><a href="qlayout.html">QLayout</a></span><span class="operator">::</span>SetNoConstraint);
<span class="preprocessor">#else</span>
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>setSizeConstraint(<span class="type"><a href="qlayout.html">QLayout</a></span><span class="operator">::</span>SetFixedSize);
<span class="preprocessor">#endif</span>
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(display<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">6</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(backspaceButton<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(clearButton<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(clearAllButton<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="number">2</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(clearMemoryButton<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">0</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(readMemoryButton<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">0</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(setMemoryButton<span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">0</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(addToMemoryButton<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">0</span>);
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">1</span>; i <span class="operator">&lt;</span> NumDigitButtons; <span class="operator">+</span><span class="operator">+</span>i) {
<span class="type">int</span> row <span class="operator">=</span> ((<span class="number">9</span> <span class="operator">-</span> i) <span class="operator">/</span> <span class="number">3</span>) <span class="operator">+</span> <span class="number">2</span>;
<span class="type">int</span> column <span class="operator">=</span> ((i <span class="operator">-</span> <span class="number">1</span>) <span class="operator">%</span> <span class="number">3</span>) <span class="operator">+</span> <span class="number">1</span>;
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(digitButtons<span class="operator">[</span>i<span class="operator">]</span><span class="operator">,</span> row<span class="operator">,</span> column);
}
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(digitButtons<span class="operator">[</span><span class="number">0</span><span class="operator">]</span><span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">1</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(pointButton<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">2</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(changeSignButton<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">3</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(divisionButton<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">4</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(timesButton<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">4</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(minusButton<span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">4</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(plusButton<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">4</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(squareRootButton<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="number">5</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(powerButton<span class="operator">,</span> <span class="number">3</span><span class="operator">,</span> <span class="number">5</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(reciprocalButton<span class="operator">,</span> <span class="number">4</span><span class="operator">,</span> <span class="number">5</span>);
mainLayout<span class="operator">-</span><span class="operator">&gt;</span>addWidget(equalButton<span class="operator">,</span> <span class="number">5</span><span class="operator">,</span> <span class="number">5</span>);
setLayout(mainLayout);
setWindowTitle(tr(<span class="string">&quot;Calculator&quot;</span>));
}
<span class="type">void</span> Calculator<span class="operator">::</span>digitClicked()
{
Button <span class="operator">*</span>clickedButton <span class="operator">=</span> qobject_cast<span class="operator">&lt;</span>Button <span class="operator">*</span><span class="operator">&gt;</span>(sender());
<span class="type">int</span> digitValue <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toInt();
<span class="keyword">if</span> (display<span class="operator">-</span><span class="operator">&gt;</span>text() <span class="operator">=</span><span class="operator">=</span> <span class="string">&quot;0&quot;</span> <span class="operator">&amp;</span><span class="operator">&amp;</span> digitValue <span class="operator">=</span><span class="operator">=</span> <span class="number">0.0</span>)
<span class="keyword">return</span>;
<span class="keyword">if</span> (waitingForOperand) {
display<span class="operator">-</span><span class="operator">&gt;</span>clear();
waitingForOperand <span class="operator">=</span> <span class="keyword">false</span>;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(display<span class="operator">-</span><span class="operator">&gt;</span>text() <span class="operator">+</span> <span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(digitValue));
}
<span class="type">void</span> Calculator<span class="operator">::</span>unaryOperatorClicked()
{
Button <span class="operator">*</span>clickedButton <span class="operator">=</span> qobject_cast<span class="operator">&lt;</span>Button <span class="operator">*</span><span class="operator">&gt;</span>(sender());
<span class="type"><a href="qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">&gt;</span>text();
<span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
<span class="type">double</span> result <span class="operator">=</span> <span class="number">0.0</span>;
<span class="keyword">if</span> (clickedOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;Sqrt&quot;</span>)) {
<span class="keyword">if</span> (operand <span class="operator">&lt;</span> <span class="number">0.0</span>) {
abortOperation();
<span class="keyword">return</span>;
}
result <span class="operator">=</span> sqrt(operand);
} <span class="keyword">else</span> <span class="keyword">if</span> (clickedOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;x\262&quot;</span>)) {
result <span class="operator">=</span> pow(operand<span class="operator">,</span> <span class="number">2.0</span>);
} <span class="keyword">else</span> <span class="keyword">if</span> (clickedOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;1/x&quot;</span>)) {
<span class="keyword">if</span> (operand <span class="operator">=</span><span class="operator">=</span> <span class="number">0.0</span>) {
abortOperation();
<span class="keyword">return</span>;
}
result <span class="operator">=</span> <span class="number">1.0</span> <span class="operator">/</span> operand;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(result));
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>additiveOperatorClicked()
{
Button <span class="operator">*</span>clickedButton <span class="operator">=</span> qobject_cast<span class="operator">&lt;</span>Button <span class="operator">*</span><span class="operator">&gt;</span>(sender());
<span class="type"><a href="qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">&gt;</span>text();
<span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
<span class="keyword">if</span> (<span class="operator">!</span>pendingMultiplicativeOperator<span class="operator">.</span>isEmpty()) {
<span class="keyword">if</span> (<span class="operator">!</span>calculate(operand<span class="operator">,</span> pendingMultiplicativeOperator)) {
abortOperation();
<span class="keyword">return</span>;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(factorSoFar));
operand <span class="operator">=</span> factorSoFar;
factorSoFar <span class="operator">=</span> <span class="number">0.0</span>;
pendingMultiplicativeOperator<span class="operator">.</span>clear();
}
<span class="keyword">if</span> (<span class="operator">!</span>pendingAdditiveOperator<span class="operator">.</span>isEmpty()) {
<span class="keyword">if</span> (<span class="operator">!</span>calculate(operand<span class="operator">,</span> pendingAdditiveOperator)) {
abortOperation();
<span class="keyword">return</span>;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(sumSoFar));
} <span class="keyword">else</span> {
sumSoFar <span class="operator">=</span> operand;
}
pendingAdditiveOperator <span class="operator">=</span> clickedOperator;
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>multiplicativeOperatorClicked()
{
Button <span class="operator">*</span>clickedButton <span class="operator">=</span> qobject_cast<span class="operator">&lt;</span>Button <span class="operator">*</span><span class="operator">&gt;</span>(sender());
<span class="type"><a href="qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">&gt;</span>text();
<span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
<span class="keyword">if</span> (<span class="operator">!</span>pendingMultiplicativeOperator<span class="operator">.</span>isEmpty()) {
<span class="keyword">if</span> (<span class="operator">!</span>calculate(operand<span class="operator">,</span> pendingMultiplicativeOperator)) {
abortOperation();
<span class="keyword">return</span>;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(factorSoFar));
} <span class="keyword">else</span> {
factorSoFar <span class="operator">=</span> operand;
}
pendingMultiplicativeOperator <span class="operator">=</span> clickedOperator;
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>equalClicked()
{
<span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
<span class="keyword">if</span> (<span class="operator">!</span>pendingMultiplicativeOperator<span class="operator">.</span>isEmpty()) {
<span class="keyword">if</span> (<span class="operator">!</span>calculate(operand<span class="operator">,</span> pendingMultiplicativeOperator)) {
abortOperation();
<span class="keyword">return</span>;
}
operand <span class="operator">=</span> factorSoFar;
factorSoFar <span class="operator">=</span> <span class="number">0.0</span>;
pendingMultiplicativeOperator<span class="operator">.</span>clear();
}
<span class="keyword">if</span> (<span class="operator">!</span>pendingAdditiveOperator<span class="operator">.</span>isEmpty()) {
<span class="keyword">if</span> (<span class="operator">!</span>calculate(operand<span class="operator">,</span> pendingAdditiveOperator)) {
abortOperation();
<span class="keyword">return</span>;
}
pendingAdditiveOperator<span class="operator">.</span>clear();
} <span class="keyword">else</span> {
sumSoFar <span class="operator">=</span> operand;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(sumSoFar));
sumSoFar <span class="operator">=</span> <span class="number">0.0</span>;
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>pointClicked()
{
<span class="keyword">if</span> (waitingForOperand)
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="string">&quot;0&quot;</span>);
<span class="keyword">if</span> (<span class="operator">!</span>display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>contains(<span class="string">&quot;.&quot;</span>))
display<span class="operator">-</span><span class="operator">&gt;</span>setText(display<span class="operator">-</span><span class="operator">&gt;</span>text() <span class="operator">+</span> tr(<span class="string">&quot;.&quot;</span>));
waitingForOperand <span class="operator">=</span> <span class="keyword">false</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>changeSignClicked()
{
<span class="type"><a href="qstring.html">QString</a></span> text <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text();
<span class="type">double</span> value <span class="operator">=</span> text<span class="operator">.</span>toDouble();
<span class="keyword">if</span> (value <span class="operator">&gt;</span> <span class="number">0.0</span>) {
text<span class="operator">.</span>prepend(tr(<span class="string">&quot;-&quot;</span>));
} <span class="keyword">else</span> <span class="keyword">if</span> (value <span class="operator">&lt;</span> <span class="number">0.0</span>) {
text<span class="operator">.</span>remove(<span class="number">0</span><span class="operator">,</span> <span class="number">1</span>);
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(text);
}
<span class="type">void</span> Calculator<span class="operator">::</span>backspaceClicked()
{
<span class="keyword">if</span> (waitingForOperand)
<span class="keyword">return</span>;
<span class="type"><a href="qstring.html">QString</a></span> text <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text();
text<span class="operator">.</span>chop(<span class="number">1</span>);
<span class="keyword">if</span> (text<span class="operator">.</span>isEmpty()) {
text <span class="operator">=</span> <span class="string">&quot;0&quot;</span>;
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
display<span class="operator">-</span><span class="operator">&gt;</span>setText(text);
}
<span class="type">void</span> Calculator<span class="operator">::</span>clear()
{
<span class="keyword">if</span> (waitingForOperand)
<span class="keyword">return</span>;
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="string">&quot;0&quot;</span>);
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>clearAll()
{
sumSoFar <span class="operator">=</span> <span class="number">0.0</span>;
factorSoFar <span class="operator">=</span> <span class="number">0.0</span>;
pendingAdditiveOperator<span class="operator">.</span>clear();
pendingMultiplicativeOperator<span class="operator">.</span>clear();
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="string">&quot;0&quot;</span>);
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>clearMemory()
{
sumInMemory <span class="operator">=</span> <span class="number">0.0</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>readMemory()
{
display<span class="operator">-</span><span class="operator">&gt;</span>setText(<span class="type"><a href="qstring.html">QString</a></span><span class="operator">::</span>number(sumInMemory));
waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>;
}
<span class="type">void</span> Calculator<span class="operator">::</span>setMemory()
{
equalClicked();
sumInMemory <span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
}
<span class="type">void</span> Calculator<span class="operator">::</span>addToMemory()
{
equalClicked();
sumInMemory <span class="operator">+</span><span class="operator">=</span> display<span class="operator">-</span><span class="operator">&gt;</span>text()<span class="operator">.</span>toDouble();
}
Button <span class="operator">*</span>Calculator<span class="operator">::</span>createButton(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&amp;</span>text<span class="operator">,</span> <span class="keyword">const</span> <span class="type">char</span> <span class="operator">*</span>member)
{
Button <span class="operator">*</span>button <span class="operator">=</span> <span class="keyword">new</span> Button(text);
connect(button<span class="operator">,</span> SIGNAL(clicked())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> member);
<span class="keyword">return</span> button;
}
<span class="type">void</span> Calculator<span class="operator">::</span>abortOperation()
{
clearAll();
display<span class="operator">-</span><span class="operator">&gt;</span>setText(tr(<span class="string">&quot;####&quot;</span>));
}
<span class="type">bool</span> Calculator<span class="operator">::</span>calculate(<span class="type">double</span> rightOperand<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&amp;</span>pendingOperator)
{
<span class="keyword">if</span> (pendingOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;+&quot;</span>)) {
sumSoFar <span class="operator">+</span><span class="operator">=</span> rightOperand;
} <span class="keyword">else</span> <span class="keyword">if</span> (pendingOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;-&quot;</span>)) {
sumSoFar <span class="operator">-</span><span class="operator">=</span> rightOperand;
} <span class="keyword">else</span> <span class="keyword">if</span> (pendingOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;\327&quot;</span>)) {
factorSoFar <span class="operator">*</span><span class="operator">=</span> rightOperand;
} <span class="keyword">else</span> <span class="keyword">if</span> (pendingOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">&quot;\367&quot;</span>)) {
<span class="keyword">if</span> (rightOperand <span class="operator">=</span><span class="operator">=</span> <span class="number">0.0</span>)
<span class="keyword">return</span> <span class="keyword">false</span>;
factorSoFar <span class="operator">/</span><span class="operator">=</span> rightOperand;
}
<span class="keyword">return</span> <span class="keyword">true</span>;
}</pre>
</div>
<!-- @@@widgets/calculator/calculator.cpp -->
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