<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>calculator.cpp Example File | Qt Widgets 5.9</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.9</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-widgets-calculator-example.html">Calculator Example</a></td><td >calculator.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">calculator.cpp Example File</h1> <span class="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) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "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 ** "AS IS" 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." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include <QtWidgets></span> <span class="preprocessor">#include <cmath></span> <span class="preprocessor">#include "button.h"</span> <span class="preprocessor">#include "calculator.h"</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">"0"</span>); display<span class="operator">-</span><span class="operator">></span>setReadOnly(<span class="keyword">true</span>); display<span class="operator">-</span><span class="operator">></span>setAlignment(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>AlignRight); display<span class="operator">-</span><span class="operator">></span>setMaxLength(<span class="number">15</span>); <span class="type"><a href="../qtgui/qfont.html">QFont</a></span> font <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">></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"><</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="../qtcore/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">"."</span>)<span class="operator">,</span> SLOT(pointClicked())); Button <span class="operator">*</span>changeSignButton <span class="operator">=</span> createButton(tr(<span class="string">"\302\261"</span>)<span class="operator">,</span> SLOT(changeSignClicked())); Button <span class="operator">*</span>backspaceButton <span class="operator">=</span> createButton(tr(<span class="string">"Backspace"</span>)<span class="operator">,</span> SLOT(backspaceClicked())); Button <span class="operator">*</span>clearButton <span class="operator">=</span> createButton(tr(<span class="string">"Clear"</span>)<span class="operator">,</span> SLOT(clear())); Button <span class="operator">*</span>clearAllButton <span class="operator">=</span> createButton(tr(<span class="string">"Clear All"</span>)<span class="operator">,</span> SLOT(clearAll())); Button <span class="operator">*</span>clearMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">"MC"</span>)<span class="operator">,</span> SLOT(clearMemory())); Button <span class="operator">*</span>readMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">"MR"</span>)<span class="operator">,</span> SLOT(readMemory())); Button <span class="operator">*</span>setMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">"MS"</span>)<span class="operator">,</span> SLOT(setMemory())); Button <span class="operator">*</span>addToMemoryButton <span class="operator">=</span> createButton(tr(<span class="string">"M+"</span>)<span class="operator">,</span> SLOT(addToMemory())); Button <span class="operator">*</span>divisionButton <span class="operator">=</span> createButton(tr(<span class="string">"\303\267"</span>)<span class="operator">,</span> SLOT(multiplicativeOperatorClicked())); Button <span class="operator">*</span>timesButton <span class="operator">=</span> createButton(tr(<span class="string">"\303\227"</span>)<span class="operator">,</span> SLOT(multiplicativeOperatorClicked())); Button <span class="operator">*</span>minusButton <span class="operator">=</span> createButton(tr(<span class="string">"-"</span>)<span class="operator">,</span> SLOT(additiveOperatorClicked())); Button <span class="operator">*</span>plusButton <span class="operator">=</span> createButton(tr(<span class="string">"+"</span>)<span class="operator">,</span> SLOT(additiveOperatorClicked())); Button <span class="operator">*</span>squareRootButton <span class="operator">=</span> createButton(tr(<span class="string">"Sqrt"</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked())); Button <span class="operator">*</span>powerButton <span class="operator">=</span> createButton(tr(<span class="string">"x\302\262"</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked())); Button <span class="operator">*</span>reciprocalButton <span class="operator">=</span> createButton(tr(<span class="string">"1/x"</span>)<span class="operator">,</span> SLOT(unaryOperatorClicked())); Button <span class="operator">*</span>equalButton <span class="operator">=</span> createButton(tr(<span class="string">"="</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>; mainLayout<span class="operator">-</span><span class="operator">></span>setSizeConstraint(<span class="type"><a href="qlayout.html">QLayout</a></span><span class="operator">::</span>SetFixedSize); mainLayout<span class="operator">-</span><span class="operator">></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">></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">></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">></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">></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">></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">></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">></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"><</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">></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">></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">></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">></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">></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">></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">></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">></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">></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">></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">></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">></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">"Calculator"</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"><</span>Button <span class="operator">*</span><span class="operator">></span>(sender()); <span class="type">int</span> digitValue <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>toInt(); <span class="keyword">if</span> (display<span class="operator">-</span><span class="operator">></span>text() <span class="operator">=</span><span class="operator">=</span> <span class="string">"0"</span> <span class="operator">&</span><span class="operator">&</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">></span>clear(); waitingForOperand <span class="operator">=</span> <span class="keyword">false</span>; } display<span class="operator">-</span><span class="operator">></span>setText(display<span class="operator">-</span><span class="operator">></span>text() <span class="operator">+</span> <span class="type"><a href="../qtcore/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"><</span>Button <span class="operator">*</span><span class="operator">></span>(sender()); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">></span>text(); <span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">"Sqrt"</span>)) { <span class="keyword">if</span> (operand <span class="operator"><</span> <span class="number">0.0</span>) { abortOperation(); <span class="keyword">return</span>; } result <span class="operator">=</span> std<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">"x\302\262"</span>)) { result <span class="operator">=</span> std<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">"1/x"</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">></span>setText(<span class="type"><a href="../qtcore/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"><</span>Button <span class="operator">*</span><span class="operator">></span>(sender()); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">></span>text(); <span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">></span>setText(<span class="type"><a href="../qtcore/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">></span>setText(<span class="type"><a href="../qtcore/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"><</span>Button <span class="operator">*</span><span class="operator">></span>(sender()); <span class="type"><a href="../qtcore/qstring.html">QString</a></span> clickedOperator <span class="operator">=</span> clickedButton<span class="operator">-</span><span class="operator">></span>text(); <span class="type">double</span> operand <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">></span>setText(<span class="type"><a href="../qtcore/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">></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">></span>setText(<span class="type"><a href="../qtcore/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">></span>setText(<span class="string">"0"</span>); <span class="keyword">if</span> (<span class="operator">!</span>display<span class="operator">-</span><span class="operator">></span>text()<span class="operator">.</span>contains(<span class="char">'.'</span>)) display<span class="operator">-</span><span class="operator">></span>setText(display<span class="operator">-</span><span class="operator">></span>text() <span class="operator">+</span> tr(<span class="string">"."</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="../qtcore/qstring.html">QString</a></span> text <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">></span> <span class="number">0.0</span>) { text<span class="operator">.</span>prepend(tr(<span class="string">"-"</span>)); } <span class="keyword">else</span> <span class="keyword">if</span> (value <span class="operator"><</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">></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="../qtcore/qstring.html">QString</a></span> text <span class="operator">=</span> display<span class="operator">-</span><span class="operator">></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">"0"</span>; waitingForOperand <span class="operator">=</span> <span class="keyword">true</span>; } display<span class="operator">-</span><span class="operator">></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">></span>setText(<span class="string">"0"</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">></span>setText(<span class="string">"0"</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">></span>setText(<span class="type"><a href="../qtcore/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">></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">></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="../qtcore/qstring.html">QString</a></span> <span class="operator">&</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">></span>setText(tr(<span class="string">"####"</span>)); } bool 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="../qtcore/qstring.html">QString</a></span> <span class="operator">&</span>pendingOperator) { <span class="keyword">if</span> (pendingOperator <span class="operator">=</span><span class="operator">=</span> tr(<span class="string">"+"</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">"-"</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">"\303\227"</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">"\303\267"</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 --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2017 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>