//************************************** //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 calculator 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 menu 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 menu 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 frame 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 displayed to degrees if (buttonText == "todeg") display.setText(Double.toString(Math.toDegrees(displayNumber))); // this will convert the numbers displayed 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 visible. 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 visible. 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 buttonPressed 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