//**************************************
//
//HTML for :Simple/Scientific Calculator
//
//**************************************
//
/**
Alogorithm for Calculator(Basic And Scientific)
Author: Inder Mohan Singh
Date Started: 12/12/2000
Date Finished: 16/12/2000
Sequence to create a GUI for Calculator
1. Create a Calculator Frame (size 200 by 270)
2. Add MenuBar to it.
3. Add MenuItem (CheckBox type Basic And Extended)
4. Add TextField (to show the result of the calculations)
5. Add CheckBox for radians and degree
6. Add Button to the Frame (20 for basic and another 8 for extended)
7. The following Action/Item methods to be included
(a) actionPerformed(ActionEvent ae){ all the action performed
on the calculator will be noted by this method like pressing
add(+) button etc}
(b) itemStateChanged(ItemEvent ie){ this will checks on the menubar
itemse.g. if you click on the extended item of View menu you will
see the extended view of the calculator}
8. The other methods/classes to be used
(i) makeCalculator(){ this will build the GUI for the calculator}
(ii) resetButtons (num) { this will reset the buttons i.e. change the
property to false}
(iii)reciprocal(num){ if num is zero than error message else num =1/num}
(iv) changeSign(num){ change the sign of the num}
(v) factorial(num){ if num is less than 1 error message else do the factorial}
(vi) class MessageBox extends Dialog implements ActionListener {
this class is called from other methods to display the error
messages.Make a constructor}
*/
import java.awt.*;
import java.awt.event.*;
// class CalcFrame for creating a calcul
// ator frame and added windolistener to
// close the calculator
class CalcFrame extends Frame {
CalcFrame( String str) {
// call to superclass
super(str);
// to close the calculator(Frame)
addWindowListener(new WindowAdapter() {
public void windowClosing (WindowEvent we) {
System.exit(0);
}
});
}
}
// main class Calculator implemnets two
// interfaces ActionListener
// and ItemListener
public class Calculator implements ActionListener, ItemListener {
// creating instances of objects
CalcFrame fr;
MenuBar mb;
Menu view, font, about;
MenuItem bold, regular, author;
CheckboxMenuItem basic, scientific;
CheckboxGroup cbg;
Checkbox radians, degrees;
TextField display;
Button key[] = new Button[20]; // creates a button object array of 20
Button clearAll, clearEntry, round;
Button scientificKey[] = new Button[10]; // creates a button array of 8
// declaring variables
boolean addButtonPressed, subtractButtonPressed, multiplyButtonPressed;
boolean divideButtonPressed, decimalPointPressed, powerButtonPressed;
boolean roundButtonPressed = false;
double initialNumber;// the first number for the two number operation
double currentNumber = 0; // the number shown in the screen while it is being pressed
int decimalPlaces = 0;
// main function
public static void main (String args[]) {
// constructor
Calculator calc = new Calculator();
calc.makeCalculator();
}
public void makeCalculator() {
// size of the button
final int BWIDTH = 25;
final int BHEIGHT = 25;
int count =1;
// create frame for the calculator
fr = new CalcFrame("Basic Calculator");
// set the size
fr.setSize(200,270);
fr.setBackground(Color.blue);;
// create a menubar for the frame
mb = new MenuBar();
// add menu the menubar
view = new Menu("View");
font = new Menu ("Font");
about = new Menu("About");
// create instance of object for View me
// nu
basic = new CheckboxMenuItem("Basic",true);
// add a listener to receive item events
// when the state of an item changes
basic.addItemListener(this);
scientific = new CheckboxMenuItem("Scientific");
// add a listener to receive item events
// when the state of an item changes
scientific.addItemListener(this);
// create instance of object for font me
// nu
bold = new MenuItem("Arial Bold");
bold.addActionListener(this);
regular = new MenuItem("Arial Regular");
regular.addActionListener(this);
// for about menu
author = new MenuItem("Author");
author.addActionListener(this);
// add the items in the menu
view.add(basic);
view.add(scientific);
font.add(bold);
font.add(regular);
about.add(author);
// add the menus in the menubar
mb.add(view);
mb.add(font);
mb.add(about);
// add menubar to the frame
fr.setMenuBar(mb);
// override the layout manager
fr.setLayout(null);
// set the initial numbers that is 1 to
// 9
for (int row = 0; row < 3; ++row) {
for (int col = 0; col < 3; ++col) {
// this will set the key from 1 to 9
key[count] = new Button(Integer.toString(count));
key[count].addActionListener(this);
// set the boundry for the keys
key[count].setBounds(30*(col + 1), 30*(row + 4),BWIDTH,BHEIGHT);
key[count].setBackground(Color.yellow);
// add to the frame
fr.add(key[count++]);
}
}
// Now create, addlistener and add to fr
// ame all other keys
//0
key[0] = new Button("0");
key[0].addActionListener(this);
key[0].setBounds(30,210,BWIDTH,BHEIGHT);
key[0].setBackground(Color.yellow);
fr.add(key[0]);
//decimal
key[10] = new Button(".");
key[10].addActionListener(this);
key[10].setBounds(60,210,BWIDTH,BHEIGHT);
key[10].setBackground(Color.yellow);
fr.add(key[10]);
//equals to
key[11] = new Button("=");
key[11].addActionListener(this);
key[11].setBounds(90,210,BWIDTH,BHEIGHT);
key[11].setBackground(Color.yellow);
fr.add(key[11]);
//multiply
key[12] = new Button("*");
key[12].addActionListener(this);
key[12].setBounds(120,120,BWIDTH,BHEIGHT);
key[12].setBackground(Color.yellow);
fr.add(key[12]);
//divide
key[13] = new Button("/");
key[13].addActionListener(this);
key[13].setBounds(120,150,BWIDTH,BHEIGHT);
key[13].setBackground(Color.yellow);
fr.add(key[13]);
//addition
key[14] = new Button("+");
key[14].addActionListener(this);
key[14].setBounds(120,180,BWIDTH,BHEIGHT);
key[14].setBackground(Color.yellow);
fr.add(key[14]);
//subtract
key[15] = new Button("-");
key[15].addActionListener(this);
key[15].setBounds(120,210,BWIDTH,BHEIGHT);
key[15].setBackground(Color.yellow);
fr.add(key[15]);
//reciprocal
key[16] = new Button("1/x");
key[16].addActionListener(this);
key[16].setBounds(150,120,BWIDTH,BHEIGHT);
key[16].setBackground(Color.yellow);
fr.add(key[16]);
//power
key[17] = new Button("x^n");
key[17].addActionListener(this);
key[17].setBounds(150,150,BWIDTH,BHEIGHT);
key[17].setBackground(Color.yellow);
fr.add(key[17]);
//change sign
key[18] = new Button("+/-");
key[18].addActionListener(this);
key[18].setBounds(150,180,BWIDTH,BHEIGHT);
key[18].setBackground(Color.yellow);
fr.add(key[18]);
//factorial
key[19] = new Button("x!");
key[19].addActionListener(this);
key[19].setBounds(150,210,BWIDTH,BHEIGHT);
key[19].setBackground(Color.yellow);
fr.add(key[19]);
// CA
clearAll = new Button("CA");
clearAll.addActionListener(this);
clearAll.setBounds(30, 240, BWIDTH+20, BHEIGHT);
clearAll.setBackground(Color.yellow);
fr.add(clearAll);
// CE
clearEntry = new Button("CE");
clearEntry.addActionListener(this);
clearEntry.setBounds(80, 240, BWIDTH+20, BHEIGHT);
clearEntry.setBackground(Color.yellow);
fr.add(clearEntry);
// round
round = new Button("Round");
round.addActionListener(this);
round.setBounds(130, 240, BWIDTH+20, BHEIGHT);
round.setBackground(Color.yellow);
fr.add(round);
// set display area
display = new TextField("0");
display.setBounds(30,90,150,20);
display.setBackground(Color.white);
// key for scientific calculator
// Sine
scientificKey[0] = new Button("Sin");
scientificKey[0].addActionListener(this);
scientificKey[0].setBounds(180, 120, BWIDTH + 10, BHEIGHT);
scientificKey[0].setVisible(false);
scientificKey[0].setBackground(Color.yellow);
fr.add(scientificKey[0]);
// cosine
scientificKey[1] = new Button("Cos");
scientificKey[1].addActionListener(this);
scientificKey[1].setBounds(180, 150, BWIDTH + 10, BHEIGHT);
scientificKey[1].setBackground(Color.yellow);
scientificKey[1].setVisible(false);
fr.add(scientificKey[1]);
// Tan
scientificKey[2] = new Button("Tan");
scientificKey[2].addActionListener(this);
scientificKey[2].setBounds(180, 180, BWIDTH + 10, BHEIGHT);
scientificKey[2].setBackground(Color.yellow);
scientificKey[2].setVisible(false);
fr.add(scientificKey[2]);
// PI
scientificKey[3] = new Button("Pi");
scientificKey[3].addActionListener(this);
scientificKey[3].setBounds(180, 210, BWIDTH + 10, BHEIGHT);
scientificKey[3].setBackground(Color.yellow);
scientificKey[3].setVisible(false);
fr.add(scientificKey[3]);
// aSine
scientificKey[4] = new Button("aSin");
scientificKey[4].addActionListener(this);
scientificKey[4].setBounds(220, 120, BWIDTH + 10, BHEIGHT);
scientificKey[4].setBackground(Color.yellow);
scientificKey[4].setVisible(false);
fr.add(scientificKey[4]);
// aCos
scientificKey[5] = new Button("aCos");
scientificKey[5].addActionListener(this);
scientificKey[5].setBounds(220, 150, BWIDTH + 10, BHEIGHT);
scientificKey[5].setBackground(Color.yellow);
scientificKey[5].setVisible(false);
fr.add(scientificKey[5]);
// aTan
scientificKey[6] = new Button("aTan");
scientificKey[6].addActionListener(this);
scientificKey[6].setBounds(220, 180, BWIDTH + 10, BHEIGHT);
scientificKey[6].setBackground(Color.yellow);
scientificKey[6].setVisible(false);
fr.add(scientificKey[6]);
// E
scientificKey[7] = new Button("E");
scientificKey[7].addActionListener(this);
scientificKey[7].setBounds(220, 210, BWIDTH + 10, BHEIGHT);
scientificKey[7].setBackground(Color.yellow);
scientificKey[7].setVisible(false);
fr.add(scientificKey[7]);
// to degrees
scientificKey[8] = new Button("todeg");
scientificKey[8].addActionListener(this);
scientificKey[8].setBounds(180, 240, BWIDTH + 10, BHEIGHT);
scientificKey[8].setBackground(Color.yellow);
scientificKey[8].setVisible(false);
fr.add(scientificKey[8]);
// to radians
scientificKey[9] = new Button("torad");
scientificKey[9].addActionListener(this);
scientificKey[9].setBounds(220, 240, BWIDTH + 10, BHEIGHT);
scientificKey[9].setBackground(Color.yellow);
scientificKey[9].setVisible(false);
fr.add(scientificKey[9]);
cbg = new CheckboxGroup();
degrees = new Checkbox("Degrees", cbg, true);
radians = new Checkbox("Radians", cbg, false);
degrees.addItemListener(this);
radians.addItemListener(this);
degrees.setBounds(185, 75, 3 * BWIDTH, BHEIGHT);
radians.setBounds(185, 95, 3 * BWIDTH, BHEIGHT);
degrees.setVisible(false);
radians.setVisible(false);
fr.add(degrees);
fr.add(radians);
fr.add(display);
fr.setVisible(true);
} // end of makeCalculator
public void actionPerformed(ActionEvent ae) {
String buttonText = ae.getActionCommand();
double displayNumber = Double.valueOf(display.getText()).doubleValue();
// if the button pressed text is 0 to 9
if((buttonText.charAt(0) >= '0') & (buttonText.charAt(0) <= '9')) {
if(decimalPointPressed) {
for (int i=1;i <=decimalPlaces; ++i)
currentNumber *= 10;
currentNumber +=(int)buttonText.charAt(0)- (int)'0';
for (int i=1;i <=decimalPlaces; ++i) {
currentNumber /=10;
}
++decimalPlaces;
display.setText(Double.toString(currentNumber));
}
else if (roundButtonPressed) {
int decPlaces = (int)buttonText.charAt(0) - (int)'0';
for (int i=0; i< decPlaces; ++i)
displayNumber *=10;
displayNumber = Math.round(displayNumber);
for (int i = 0; i < decPlaces; ++i) {
displayNumber /=10;
}
display.setText(Double.toString(displayNumber));
roundButtonPressed = false;
}
else {
currentNumber = currentNumber * 10 + (int)buttonText.charAt(0)-(int)'0';
display.setText(Integer.toString((int)currentNumber));
}
}
// if button pressed is addition
if(buttonText == "+") {
addButtonPressed = true;
initialNumber = displayNumber;
currentNumber = 0;
decimalPointPressed = false;
}
// if button pressed is subtract
if (buttonText == "-") {
subtractButtonPressed = true;
initialNumber = displayNumber;
currentNumber = 0;
decimalPointPressed = false;
}
// if button pressed is divide
if (buttonText == "/") {
divideButtonPressed = true;
initialNumber = displayNumber;
currentNumber = 0;
decimalPointPressed = false;
}
// if button pressed is multiply
if (buttonText == "*") {
multiplyButtonPressed = true;
initialNumber = displayNumber;
currentNumber = 0;
decimalPointPressed = false;
}
// if button pressed is reciprocal
if (buttonText == "1/x") {
// call reciprocal method
display.setText(reciprocal(displayNumber));
currentNumber = 0;
decimalPointPressed = false;
}
// if button is pressed to change a sign
//
if (buttonText == "+/-") {
// call changesign meyhod to change the
// sign
display.setText(changeSign(displayNumber));
currentNumber = 0;
decimalPointPressed = false;
}
// factorial button
if (buttonText == "x!") {
display.setText(factorial(displayNumber));
currentNumber = 0;
decimalPointPressed = false;
}
// power button
if (buttonText == "x^n") {
powerButtonPressed = true;
initialNumber = displayNumber;
currentNumber = 0;
decimalPointPressed = false;
}
// now for scientific buttons
if (buttonText == "Sin") {
if (degrees.getState())
display.setText(Double.toString(Math.sin(Math.PI * displayNumber/180)));
else {
display.setText(Double.toString(Math.sin(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
if (buttonText == "Cos") {
if (degrees.getState())
display.setText(Double.toString(Math.cos(Math.PI * displayNumber/180)));
else{
display.setText(Double.toString(Math.cos(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
if (buttonText == "Tan") {
if (degrees.getState())
display.setText(Double.toString(Math.tan(Math.PI * displayNumber/180)));
else {
display.setText(Double.toString(Math.tan(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
if (buttonText == "aSin") {
if (degrees.getState())
display.setText(Double.toString(Math.asin(displayNumber)* 180/Math.PI ));
else {
display.setText(Double.toString(Math.asin(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
if (buttonText == "aCos") {
if (degrees.getState())
display.setText(Double.toString(Math.acos(displayNumber)* 180/Math.PI ));
else {
display.setText(Double.toString(Math.acos(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
if (buttonText == "aTan") {
if (degrees.getState())
display.setText(Double.toString(Math.atan(displayNumber)* 180/Math.PI ));
else {
display.setText(Double.toString(Math.atan(displayNumber)));
currentNumber = 0;
decimalPointPressed = false;
}
}
// this will convert the numbers display
// ed to degrees
if (buttonText == "todeg")
display.setText(Double.toString(Math.toDegrees(displayNumber)));
// this will convert the numbers display
// ed to radians
if (buttonText == "torad")
display.setText(Double.toString(Math.toRadians(displayNumber)));
if (buttonText == "Pi") {
display.setText(Double.toString(Math.PI));
currentNumber =0;
decimalPointPressed = false;
}
if (buttonText == "Round")
roundButtonPressed = true;
// check if decimal point is pressed
if (buttonText == ".") {
String displayedNumber = display.getText();
boolean decimalPointFound = false;
int i;
decimalPointPressed = true;
// check for decimal point
for (i =0; i < displayedNumber.length(); ++i) {
if(displayedNumber.charAt(i) == '.') {
decimalPointFound = true;
continue;
}
}
if (!decimalPointFound)
decimalPlaces = 1;
}
if(buttonText == "CA"){
// set all buttons to false
resetAllButtons();
display.setText("0");
currentNumber = 0;
}
if (buttonText == "CE") {
display.setText("0");
currentNumber = 0;
decimalPointPressed = false;
}
if (buttonText == "E") {
display.setText(Double.toString(Math.E));
currentNumber = 0;
decimalPointPressed = false;
}
// the main action
if (buttonText == "=") {
currentNumber = 0;
// if add button is pressed
if(addButtonPressed)
display.setText(Double.toString(initialNumber + displayNumber));
// if subtract button is pressed
if(subtractButtonPressed)
display.setText(Double.toString(initialNumber - displayNumber));
// if divide button is pressed
if (divideButtonPressed) {
// check if the divisor is zero
if(displayNumber == 0) {
MessageBox mb = new MessageBox ( fr, "Error ", true, "Cannot divide by zero.");
mb.show();
}
else
display.setText(Double.toString(initialNumber/displayNumber));
}
// if multiply button is pressed
if(multiplyButtonPressed)
display.setText(Double.toString(initialNumber * displayNumber));
// if power button is pressed
if (powerButtonPressed)
display.setText(power(initialNumber, displayNumber));
// set all the buttons to false
resetAllButtons();
}
if (buttonText == "Arial Regular") {
for (int i =0; i < 10; ++i)
key[i].setFont(new Font("Arial", Font.PLAIN, 12));
}
if (buttonText == "Arial Bold") {
for (int i =0; i < 10; ++i)
key[i].setFont(new Font("Arial", Font.BOLD, 12));
}
if (buttonText == "Author") {
MessageBox mb = new MessageBox ( fr, "Calculator ver 1.0 beta ", true, "Author: Inder Mohan Singh.");
mb.show();
}
} // end of action events
public void itemStateChanged(ItemEvent ie) {
if (ie.getItem() == "Basic") {
basic.setState(true);
scientific.setState(false);
fr.setTitle("Basic Calculator");
fr.setSize(200,270);
// check if the scientific keys are visi
// ble. if true hide them
if (scientificKey[0].isVisible()) {
for (int i=0; i < 8; ++i)
scientificKey[i].setVisible(false);
radians.setVisible(false);
degrees.setVisible(false);
}
}
if (ie.getItem() == "Scientific") {
basic.setState(false);
scientific.setState(true);
fr.setTitle("Scientific Calculator");
fr.setSize(270,270);
// check if the scientific keys are visi
// ble. if true display them
if (!scientificKey[0].isVisible()) {
for (int i=0; i < 10; ++i)
scientificKey[i].setVisible(true);
radians.setVisible(true);
degrees.setVisible(true);
}
}
} // end of itemState
// this method will reset all the button
// Pressed property to false
public void resetAllButtons() {
addButtonPressed = false;
subtractButtonPressed = false;
multiplyButtonPressed = false;
divideButtonPressed = false;
decimalPointPressed = false;
powerButtonPressed = false;
roundButtonPressed = false;
}
public String factorial(double num) {
int theNum = (int)num;
if (theNum < 1) {
MessageBox mb = new MessageBox (fr, "Facorial Error", true,
"Cannot find the factorial of numbers less than 1.");
mb.show();
return ("0");
}
else {
for (int i=(theNum -1); i > 1; --i)
theNum *= i;
return Integer.toString(theNum);
}
}
public String reciprocal(double num) {
if (num ==0) {
MessageBox mb = new MessageBox(fr,"Reciprocal Error", true,
"Cannot find the reciprocal of 0");
mb.show();
}
else
num = 1/num;
return Double.toString(num);
}
public String power (double base, double index) {
return Double.toString(Math.pow(base, index));
}
public String changeSign(double num) {
return Double.toString(-num);
}
}
class MessageBox extends Dialog implements ActionListener {
Button ok;
MessageBox(Frame f, String title, boolean mode, String message) {
super(f, title, mode);
Panel centrePanel = new Panel();
Label lbl = new Label(message);
centrePanel.add(lbl);
add(centrePanel, "Center");
Panel southPanel = new Panel();
ok = new Button ("OK");
ok.addActionListener(this);
southPanel.add(ok);
add(southPanel, "South");
pack();
addWindowListener (new WindowAdapter() {
public void windowClosing (WindowEvent we) {
System.exit(0);
}
});
}
public void actionPerformed(ActionEvent ae) {
dispose();
}
}
End of source code |
