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#include <QtGui>

#include <math.h>

#include "button.h"

#include "calculator.h"

//! [0]

Calculator::Calculator(QWidget *parent)

    : QDialog(parent)

{

    sumInMemory = 0.0;

    sumSoFar = 0.0;

    factorSoFar = 0.0;

    waitingForOperand = true;

//! [0]

//! [1]

    display = new QLineEdit("0");

//! [1] //! [2]

    display->setReadOnly(true);

    display->setAlignment(Qt::AlignRight);

    display->setMaxLength(15);

    QFont font = display->font();

    font.setPointSize(font.pointSize() + 8);

    display->setFont(font);

//! [2]

//! [4]

    for (int i = 0; i < NumDigitButtons; ++i) {

	digitButtons[i] = createButton(QString::number(i), SLOT(digitClicked()));

    }

    Button *pointButton = createButton(tr("."), SLOT(pointClicked()));

    Button *changeSignButton = createButton(tr("\261"), SLOT(changeSignClicked()));

    Button *backspaceButton = createButton(tr("Backspace"), SLOT(backspaceClicked()));

    Button *clearButton = createButton(tr("Clear"), SLOT(clear()));

    Button *clearAllButton = createButton(tr("Clear All"), SLOT(clearAll()));

    Button *clearMemoryButton = createButton(tr("MC"), SLOT(clearMemory()));

    Button *readMemoryButton = createButton(tr("MR"), SLOT(readMemory()));

    Button *setMemoryButton = createButton(tr("MS"), SLOT(setMemory()));

    Button *addToMemoryButton = createButton(tr("M+"), SLOT(addToMemory()));

    Button *divisionButton = createButton(tr("\367"), SLOT(multiplicativeOperatorClicked()));

    Button *timesButton = createButton(tr("\327"), SLOT(multiplicativeOperatorClicked()));

    Button *minusButton = createButton(tr("-"), SLOT(additiveOperatorClicked()));

    Button *plusButton = createButton(tr("+"), SLOT(additiveOperatorClicked()));

    Button *squareRootButton = createButton(tr("Sqrt"), SLOT(unaryOperatorClicked()));

    Button *powerButton = createButton(tr("x\262"), SLOT(unaryOperatorClicked()));

    Button *reciprocalButton = createButton(tr("1/x"), SLOT(unaryOperatorClicked()));

    Button *equalButton = createButton(tr("="), SLOT(equalClicked()));

//! [4]

//! [5]

    QGridLayout *mainLayout = new QGridLayout;

//! [5] //! [6]

    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"));

}

//! [6]

//! [7]

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));

}

//! [7]

//! [8]

void Calculator::unaryOperatorClicked()

//! [8] //! [9]

{

    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;

}

//! [9]

//! [10]

void Calculator::additiveOperatorClicked()

//! [10] //! [11]

{

    Button *clickedButton = qobject_cast<Button *>(sender());

    QString clickedOperator = clickedButton->text();

    double operand = display->text().toDouble();

//! [11] //! [12]

    if (!pendingMultiplicativeOperator.isEmpty()) {

//! [12] //! [13]

        if (!calculate(operand, pendingMultiplicativeOperator)) {

            abortOperation();

	    return;

        }

        display->setText(QString::number(factorSoFar));

        operand = factorSoFar;

        factorSoFar = 0.0;

        pendingMultiplicativeOperator.clear();

    }

//! [13] //! [14]

    if (!pendingAdditiveOperator.isEmpty()) {

//! [14] //! [15]

        if (!calculate(operand, pendingAdditiveOperator)) {

            abortOperation();

	    return;

        }

        display->setText(QString::number(sumSoFar));

    } else {

        sumSoFar = operand;

    }

//! [15] //! [16]

    pendingAdditiveOperator = clickedOperator;

//! [16] //! [17]

    waitingForOperand = true;

}

//! [17]

//! [18]

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;

}

//! [18]

//! [20]

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;

}

//! [20]

//! [22]

void Calculator::pointClicked()

{

    if (waitingForOperand)

        display->setText("0");

    if (!display->text().contains("."))

        display->setText(display->text() + tr("."));

    waitingForOperand = false;

}

//! [22]

//! [24]

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);

}

//! [24]

//! [26]

void Calculator::backspaceClicked()

{

    if (waitingForOperand)

        return;

    QString text = display->text();

    text.chop(1);

    if (text.isEmpty()) {

        text = "0";

        waitingForOperand = true;

    }

    display->setText(text);

}

//! [26]

//! [28]

void Calculator::clear()

{

    if (waitingForOperand)

        return;

    display->setText("0");

    waitingForOperand = true;

}

//! [28]

//! [30]

void Calculator::clearAll()

{

    sumSoFar = 0.0;

    factorSoFar = 0.0;

    pendingAdditiveOperator.clear();

    pendingMultiplicativeOperator.clear();

    display->setText("0");

    waitingForOperand = true;

}

//! [30]

//! [32]

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();

}

//! [32]

//! [34]

Button *Calculator::createButton(const QString &text, const char *member)

{

    Button *button = new Button(text);

    connect(button, SIGNAL(clicked()), this, member);

    return button;

}

//! [34]

//! [36]

void Calculator::abortOperation()

{

    clearAll();

    display->setText(tr("####"));

}

//! [36]

//! [38]

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;

}

//! [38]