/******************************************************************************** Copyright (C) 2005-2006 Trolltech ASA. All rights reserved.**** This file is part of the example classes of the Qt Toolkit.**** This file may be used under the terms of the GNU General Public** License version 2.0 as published by the Free Software Foundation** and appearing in the file LICENSE.GPL included in the packaging of** this file.  Please review the following information to ensure GNU** General Public Licensing requirements will be met:** http://www.trolltech.com/products/qt/opensource.html**** If you are unsure which license is appropriate for your use, please** review the following information:** http://www.trolltech.com/products/qt/licensing.html or contact the** sales department at sales@trolltech.com.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.******************************************************************************/#include <QtGui>#include <math.h>#include "button.h"#include "calculator.h"Calculator::Calculator(QWidget *parent)    : QDialog(parent){    sumInMemory = 0.0;    sumSoFar = 0.0;    factorSoFar = 0.0;    waitingForOperand = true;    display = new QLineEdit("0");    display->setReadOnly(true);    display->setAlignment(Qt::AlignRight);    display->setMaxLength(15);    display->installEventFilter(this);    QFont font = display->font();    font.setPointSize(font.pointSize() + 8);    display->setFont(font);    QColor digitColor(150, 205, 205);    QColor backspaceColor(225, 185, 135);    QColor memoryColor(100, 155, 155);    QColor operatorColor(155, 175, 195);    for (int i = 0; i < NumDigitButtons; ++i) {	digitButtons[i] = createButton(QString::number(i), digitColor,                                       SLOT(digitClicked()));    }    pointButton = createButton(tr("."), digitColor, SLOT(pointClicked()));    changeSignButton = createButton(tr("\261"), digitColor, SLOT(changeSignClicked()));    backspaceButton = createButton(tr("Backspace"), backspaceColor,                                   SLOT(backspaceClicked()));    clearButton = createButton(tr("Clear"), backspaceColor, SLOT(clear()));    clearAllButton = createButton(tr("Clear All"), backspaceColor.light(120),                                  SLOT(clearAll()));    clearMemoryButton = createButton(tr("MC"), memoryColor,                                     SLOT(clearMemory()));    readMemoryButton = createButton(tr("MR"), memoryColor, SLOT(readMemory()));    setMemoryButton = createButton(tr("MS"), memoryColor, SLOT(setMemory()));    addToMemoryButton = createButton(tr("M+"), memoryColor,                                     SLOT(addToMemory()));    divisionButton = createButton(tr("\367"), operatorColor,                                  SLOT(multiplicativeOperatorClicked()));    timesButton = createButton(tr("\327"), operatorColor,                               SLOT(multiplicativeOperatorClicked()));    minusButton = createButton(tr("-"), operatorColor,                               SLOT(additiveOperatorClicked()));    plusButton = createButton(tr("+"), operatorColor,                              SLOT(additiveOperatorClicked()));    squareRootButton = createButton(tr("Sqrt"), operatorColor,                                    SLOT(unaryOperatorClicked()));    powerButton = createButton(tr("x\262"), operatorColor,                               SLOT(unaryOperatorClicked()));    reciprocalButton = createButton(tr("1/x"), operatorColor,                                    SLOT(unaryOperatorClicked()));    equalButton = createButton(tr("="), operatorColor.light(120),                               SLOT(equalClicked()));    QGridLayout *mainLayout = new QGridLayout;    mainLayout->setSizeConstraint(QLayout::SetFixedSize);    mainLayout->addWidget(display, 0, 0, 1, 6);    mainLayout->addWidget(backspaceButton, 1, 0, 1, 2);    mainLayout->addWidget(clearButton, 1, 2, 1, 2);    mainLayout->addWidget(clearAllButton, 1, 4, 1, 2);    mainLayout->addWidget(clearMemoryButton, 2, 0);    mainLayout->addWidget(readMemoryButton, 3, 0);    mainLayout->addWidget(setMemoryButton, 4, 0);    mainLayout->addWidget(addToMemoryButton, 5, 0);    for (int i = 1; i < NumDigitButtons; ++i) {        int row = ((9 - i) / 3) + 2;        int column = ((i - 1) % 3) + 1;        mainLayout->addWidget(digitButtons[i], row, column);    }    mainLayout->addWidget(digitButtons[0], 5, 1);    mainLayout->addWidget(pointButton, 5, 2);    mainLayout->addWidget(changeSignButton, 5, 3);    mainLayout->addWidget(divisionButton, 2, 4);    mainLayout->addWidget(timesButton, 3, 4);    mainLayout->addWidget(minusButton, 4, 4);    mainLayout->addWidget(plusButton, 5, 4);    mainLayout->addWidget(squareRootButton, 2, 5);    mainLayout->addWidget(powerButton, 3, 5);    mainLayout->addWidget(reciprocalButton, 4, 5);    mainLayout->addWidget(equalButton, 5, 5);    setLayout(mainLayout);    setWindowTitle(tr("Calculator"));}bool Calculator::eventFilter(QObject *target, QEvent *event){    if (target == display) {        if (event->type() == QEvent::MouseButtonPress                || event->type() == QEvent::MouseButtonDblClick                || event->type() == QEvent::MouseButtonRelease                || event->type() == QEvent::ContextMenu) {            QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);            if (mouseEvent->buttons() & Qt::LeftButton) {                QPalette newPalette = palette();                newPalette.setColor(QPalette::Base,                                    display->palette().color(QPalette::Text));                newPalette.setColor(QPalette::Text,                                    display->palette().color(QPalette::Base));                display->setPalette(newPalette);            } else {                display->setPalette(palette());            }            return true;        }    }    return QDialog::eventFilter(target, event);}void Calculator::digitClicked(){    Button *clickedButton = qobject_cast<Button *>(sender());    int digitValue = clickedButton->text().toInt();    if (display->text() == "0" && digitValue == 0.0)        return;    if (waitingForOperand) {        display->clear();	waitingForOperand = false;    }    display->setText(display->text() + QString::number(digitValue));}void Calculator::unaryOperatorClicked(){    Button *clickedButton = qobject_cast<Button *>(sender());    QString clickedOperator = clickedButton->text();    double operand = display->text().toDouble();    double result = 0.0;    if (clickedOperator == tr("Sqrt")) {        if (operand < 0.0) {            abortOperation();            return;        }        result = sqrt(operand);    } else if (clickedOperator == tr("x\262")) {        result = pow(operand, 2.0);    } else if (clickedOperator == tr("1/x")) {        if (operand == 0.0) {	    abortOperation();	    return;        }        result = 1.0 / operand;    }    display->setText(QString::number(result));    waitingForOperand = true;}void Calculator::additiveOperatorClicked(){    Button *clickedButton = qobject_cast<Button *>(sender());    QString clickedOperator = clickedButton->text();    double operand = display->text().toDouble();    if (!pendingMultiplicativeOperator.isEmpty()) {        if (!calculate(operand, pendingMultiplicativeOperator)) {            abortOperation();	    return;        }        display->setText(QString::number(factorSoFar));        operand = factorSoFar;        factorSoFar = 0.0;        pendingMultiplicativeOperator.clear();    }    if (!pendingAdditiveOperator.isEmpty()) {        if (!calculate(operand, pendingAdditiveOperator)) {            abortOperation();	    return;        }        display->setText(QString::number(sumSoFar));    } else {        sumSoFar = operand;    }    pendingAdditiveOperator = clickedOperator;    waitingForOperand = true;}void Calculator::multiplicativeOperatorClicked(){    Button *clickedButton = qobject_cast<Button *>(sender());    QString clickedOperator = clickedButton->text();    double operand = display->text().toDouble();    if (!pendingMultiplicativeOperator.isEmpty()) {        if (!calculate(operand, pendingMultiplicativeOperator)) {            abortOperation();	    return;        }        display->setText(QString::number(factorSoFar));    } else {        factorSoFar = operand;    }    pendingMultiplicativeOperator = clickedOperator;    waitingForOperand = true;}void Calculator::equalClicked(){    double operand = display->text().toDouble();    if (!pendingMultiplicativeOperator.isEmpty()) {        if (!calculate(operand, pendingMultiplicativeOperator)) {            abortOperation();	    return;        }        operand = factorSoFar;        factorSoFar = 0.0;        pendingMultiplicativeOperator.clear();    }    if (!pendingAdditiveOperator.isEmpty()) {        if (!calculate(operand, pendingAdditiveOperator)) {            abortOperation();	    return;        }        pendingAdditiveOperator.clear();    } else {        sumSoFar = operand;    }    display->setText(QString::number(sumSoFar));    sumSoFar = 0.0;    waitingForOperand = true;}void Calculator::pointClicked(){    if (waitingForOperand)        display->setText("0");    if (!display->text().contains("."))        display->setText(display->text() + tr("."));    waitingForOperand = false;}void Calculator::changeSignClicked(){    QString text = display->text();    double value = text.toDouble();    if (value > 0.0) {        text.prepend(tr("-"));    } else if (value < 0.0) {        text.remove(0, 1);    }    display->setText(text);}void Calculator::backspaceClicked(){    if (waitingForOperand)        return;    QString text = display->text();    text.chop(1);    if (text.isEmpty()) {        text = "0";        waitingForOperand = true;    }    display->setText(text);}void Calculator::clear(){    if (waitingForOperand)        return;    display->setText("0");    waitingForOperand = true;}void Calculator::clearAll(){    sumSoFar = 0.0;    factorSoFar = 0.0;    pendingAdditiveOperator.clear();    pendingMultiplicativeOperator.clear();    display->setText("0");    waitingForOperand = true;}void Calculator::clearMemory(){    sumInMemory = 0.0;}void Calculator::readMemory(){    display->setText(QString::number(sumInMemory));    waitingForOperand = true;}void Calculator::setMemory(){    equalClicked();    sumInMemory = display->text().toDouble();}void Calculator::addToMemory(){    equalClicked();    sumInMemory += display->text().toDouble();}Button *Calculator::createButton(const QString &text, const QColor &color,                                 const char *member){    Button *button = new Button(text, color);    connect(button, SIGNAL(clicked()), this, member);    return button;}void Calculator::abortOperation(){    clearAll();    display->setText(tr("####"));}bool Calculator::calculate(double rightOperand, const QString &pendingOperator){    if (pendingOperator == tr("+")) {        sumSoFar += rightOperand;    } else if (pendingOperator == tr("-")) {        sumSoFar -= rightOperand;    } else if (pendingOperator == tr("\327")) {        factorSoFar *= rightOperand;    } else if (pendingOperator == tr("\367")) {	if (rightOperand == 0.0)	    return false;	factorSoFar /= rightOperand;    }    return true;}