calculator.cpp Example File
widgets/calculator/calculator.cpp
/****************************************************************************
**
** Copyright (C) 2005-2006 Trolltech AS. All rights reserved.
**
** This file is part of the documentation 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:
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** 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;
}
