#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);     QFont font = display->font();     font.setPointSize(font.pointSize() + 8);     display->setFont(font);     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()));     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")); } 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 char *member) {     Button *button = new Button(text);     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; }