import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class cal extends JFrame implements ActionListener
{
JMenuBar mb;
JMenu file, help;
JMenuItem esc, about;
JButton btn[];
JLabel lab1 = new JLabel("0");
JPanel pan1;
int i;
final int MAX_INPUT_LENGTH = 20;
final int INPUT_MODE = 0;
final int RESULT_MODE = 1;
final int ERROR_MODE = 2;
int displayMode;
boolean clearOnNextDigit;
double lastNumber;
String lastOperator;
public cal()
{
super("Calculator");
setLayout(new BorderLayout());
//creating the menu bar
mb = new JMenuBar();
setJMenuBar(mb);
file = new JMenu("File");
esc = new JMenuItem("Exit");
file.add(esc);
help = new JMenu("Help");
about = new JMenuItem("About");
help.add(about);
mb.add(file);
mb.add(help);
esc.addActionListener(this);
about.addActionListener(this);
lab1.setBackground(Color.WHITE);
lab1.setOpaque(true);
add(lab1,BorderLayout.NORTH);
pan1 = new JPanel(new GridLayout(5,4,2,3));
btn = new JButton[20];
// Create numeric Jbuttons
for(i = 0; i < 10 ; i++)
{
btn[i] = new JButton(String.valueOf(i));
}
btn[10] = new JButton("+/-");
btn[11] = new JButton(".");
btn[12] = new JButton("=");
btn[13] = new JButton("/");
btn[14] = new JButton("*");
btn[15] = new JButton("-");
btn[16] = new JButton("+");
btn[17] = new JButton("BS");
btn[18] = new JButton("C");
btn[19] = new JButton("CE");
for (i=0; i < btn.length; i++)
{
// set each Jbutton label to the value of index
btn[i].addActionListener(this);
pan1.add(btn[i]);
}
add(pan1,BorderLayout.CENTER);
for(i=0 ; i < btn.length; i++)
{
if(i < 10)
{
btn[i].setBackground(Color.LIGHT_GRAY);
btn[i].setForeground(new Color(64,128,128));
}
else
{
btn[i].setBackground(Color.GRAY);
btn[i].setForeground(Color.BLACK);
}
}
//Add buttons to keypad panel starting at top left
// First row BS,CE,C,Equal
pan1.add(btn[17]);
pan1.add(btn[19]);
pan1.add(btn[18]);
pan1.add(btn[12]);
//second row 1,2,3,Plus
for(i=1; i<=3; i++)
{
pan1.add(btn[i]);
}
pan1.add(btn[16]);
for(i=4; i<=6; i++)
{
pan1.add(btn[i]);
}
pan1.add(btn[15]);
// Third row 4,5,6,Subtract
for(i=7; i<=9; i++)
{
pan1.add(btn[i]);
}
pan1.add(btn[14]);
//Fourth Row 0,ChangeSign,DecimalPoint,Division
pan1.add(btn[0]);
pan1.add(btn[10]);
pan1.add(btn[11]);
pan1.add(btn[13]);
setSize(225,269);
pack();
setLocation(150,150);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(3);
}
public void actionPerformed(ActionEvent ae)
{
double resulr = 0;
if(ae.getSource() == esc)
System.exit(0);
else if(ae.getSource() == about)
JOptionPane.showMessageDialog(null,"This is My First Project in OOP II",""
,JOptionPane.INFORMATION_MESSAGE);
for(i = 0; i < btn.length; i++)
{
if(ae.getSource() == btn[i])
switch(i)
{
case 0:
addDigitToDisplay(i);
break;
case 1:
addDigitToDisplay(i);
break;
case 2:
addDigitToDisplay(i);
break;
case 3:
addDigitToDisplay(i);
break;
case 4:
addDigitToDisplay(i);
break;
case 5:
addDigitToDisplay(i);
break;
case 6:
addDigitToDisplay(i);
break;
case 7:
addDigitToDisplay(i);
break;
case 8:
addDigitToDisplay(i);
break;
case 9:
addDigitToDisplay(i);
break;
case 10: // ChangeSign
processSignChange();
break;
case 11: // Decimal point
addDecimalPoint();
break;
case 12: // Equal
processEquals();
break;
case 13: // Divide
processOperator("/");
break;
case 14: // Multiply
processOperator("*");
break;
case 15: // Minus
processOperator("-");
break;
case 16: // plus
processOperator("+");
break;
case 17: // Backspace
if (displayMode != ERROR_MODE)
{
setDisplayString(getDisplayString().substring(0,getDisplayString().length() - 1));
if (getDisplayString().length() < 1)
setDisplayString("0");
}
break;
case 18: // CE
clearExisting();
break;
case 19: // C
clearAll();
break;
}
}
}
void setDisplayString(String s)
{
lab1.setText(s);
}
String getDisplayString ()
{
return lab1.getText();
}
void addDigitToDisplay(int digit)
{
if (clearOnNextDigit)
setDisplayString("");
String inputString = getDisplayString();
if (inputString.indexOf("0") == 0)
{
inputString = inputString.substring(1);
}
if ((!inputString.equals("0") || digit > 0) &&(inputString.length() < MAX_INPUT_LENGTH))
{
setDisplayString(inputString + digit);
}
displayMode = INPUT_MODE;
clearOnNextDigit = false;
}
void addDecimalPoint()
{
displayMode = INPUT_MODE;
if (clearOnNextDigit)
setDisplayString("");
String inputString = getDisplayString();
// If the input string already contains a decimal point, don't
// do anything to it.
if (inputString.indexOf(".") < 0)
setDisplayString(new String(inputString + "."));
}
void processSignChange()
{
if (displayMode == INPUT_MODE)
{
String input = getDisplayString();
if (input.length() > 0 && !input.equals("0"))
{
if (input.indexOf("-") == 0)
setDisplayString(input.substring(1));
else
setDisplayString("-" + input);
}
}
else if (displayMode == RESULT_MODE)
{
double numberInDisplay = getNumberInDisplay();
if (numberInDisplay != 0)
displayResult(-numberInDisplay);
}
}
void clearAll()
{
setDisplayString("0");
lastOperator = "0";
lastNumber = 0;
displayMode = INPUT_MODE;
clearOnNextDigit = true;
}
void clearExisting()
{
setDisplayString("0");
clearOnNextDigit = true;
displayMode = INPUT_MODE;
}
double getNumberInDisplay()
{
String input = lab1.getText();
return Double.parseDouble(input);
}
void processOperator(String op)
{
double numberInDisplay = getNumberInDisplay();
lastNumber = numberInDisplay;
clearOnNextDigit = true;
lastOperator = op;
}
void processEquals()
{
double result = 0;
if (displayMode != ERROR_MODE)
{
try
{
result = processLastOperator();
displayResult(result);
}
catch (DivideByZeroException e) {
displayError("Cannot divide by zero!");
}
lastOperator = lastOperator;
}
}
double processLastOperator() throws DivideByZeroException
{
double result = 0;
double numberInDisplay = getNumberInDisplay();
if (lastOperator.equals("/"))
{
if (numberInDisplay == 0)
throw (new DivideByZeroException());
result = lastNumber / numberInDisplay;
}
if (lastOperator.equals("*"))
result = lastNumber * numberInDisplay;
if (lastOperator.equals("-"))
result = lastNumber - numberInDisplay;
if (lastOperator.equals("+"))
result = lastNumber + numberInDisplay;
return result;
}
void displayResult(double result)
{
setDisplayString(Double.toString(result));
lastNumber = result;
displayMode = RESULT_MODE;
clearOnNextDigit = true;
}
void displayError(String errorMessage){
setDisplayString(errorMessage);
lastNumber = 0;
displayMode = ERROR_MODE;
clearOnNextDigit = true;
}
public static void main(String arg[])
{
new cal();
}
}
JAbeer 0 Newbie Poster
gunjannigam 28 Junior Poster
import javax.swing.*; import java.awt.*; import java.awt.event.*; public class cal extends JFrame implements ActionListener { JMenuBar mb; JMenu file, help; JMenuItem esc, about; JButton btn[]; JLabel lab1 = new JLabel("0"); JPanel pan1; int i; final int MAX_INPUT_LENGTH = 20; final int INPUT_MODE = 0; final int RESULT_MODE = 1; final int ERROR_MODE = 2; int displayMode; boolean clearOnNextDigit; double lastNumber; String lastOperator; public cal() { super("Calculator"); setLayout(new BorderLayout()); //creating the menu bar mb = new JMenuBar(); setJMenuBar(mb); file = new JMenu("File"); esc = new JMenuItem("Exit"); file.add(esc); help = new JMenu("Help"); about = new JMenuItem("About"); help.add(about); mb.add(file); mb.add(help); esc.addActionListener(this); about.addActionListener(this); lab1.setBackground(Color.WHITE); lab1.setOpaque(true); add(lab1,BorderLayout.NORTH); pan1 = new JPanel(new GridLayout(5,4,2,3)); btn = new JButton[20]; // Create numeric Jbuttons for(i = 0; i < 10 ; i++) { btn[i] = new JButton(String.valueOf(i)); } btn[10] = new JButton("+/-"); btn[11] = new JButton("."); btn[12] = new JButton("="); btn[13] = new JButton("/"); btn[14] = new JButton("*"); btn[15] = new JButton("-"); btn[16] = new JButton("+"); btn[17] = new JButton("BS"); btn[18] = new JButton("C"); btn[19] = new JButton("CE"); for (i=0; i < btn.length; i++) { // set each Jbutton label to the value of index btn[i].addActionListener(this); pan1.add(btn[i]); } add(pan1,BorderLayout.CENTER); for(i=0 ; i < btn.length; i++) { if(i < 10) { btn[i].setBackground(Color.LIGHT_GRAY); btn[i].setForeground(new Color(64,128,128)); } else { btn[i].setBackground(Color.GRAY); btn[i].setForeground(Color.BLACK); } } //Add buttons to keypad panel starting at top left // First row BS,CE,C,Equal pan1.add(btn[17]); pan1.add(btn[19]); pan1.add(btn[18]); pan1.add(btn[12]); //second row 1,2,3,Plus for(i=1; i<=3; i++) { pan1.add(btn[i]); } pan1.add(btn[16]); for(i=4; i<=6; i++) { pan1.add(btn[i]); } pan1.add(btn[15]); // Third row 4,5,6,Subtract for(i=7; i<=9; i++) { pan1.add(btn[i]); } pan1.add(btn[14]); //Fourth Row 0,ChangeSign,DecimalPoint,Division pan1.add(btn[0]); pan1.add(btn[10]); pan1.add(btn[11]); pan1.add(btn[13]); setSize(225,269); pack(); setLocation(150,150); setVisible(true); setResizable(false); setDefaultCloseOperation(3); } public void actionPerformed(ActionEvent ae) { double resulr = 0; if(ae.getSource() == esc) System.exit(0); else if(ae.getSource() == about) JOptionPane.showMessageDialog(null,"This is My First Project in OOP II","" ,JOptionPane.INFORMATION_MESSAGE); for(i = 0; i < btn.length; i++) { if(ae.getSource() == btn[i]) switch(i) { case 0: addDigitToDisplay(i); break; case 1: addDigitToDisplay(i); break; case 2: addDigitToDisplay(i); break; case 3: addDigitToDisplay(i); break; case 4: addDigitToDisplay(i); break; case 5: addDigitToDisplay(i); break; case 6: addDigitToDisplay(i); break; case 7: addDigitToDisplay(i); break; case 8: addDigitToDisplay(i); break; case 9: addDigitToDisplay(i); break; case 10: // ChangeSign processSignChange(); break; case 11: // Decimal point addDecimalPoint(); break; case 12: // Equal processEquals(); break; case 13: // Divide processOperator("/"); break; case 14: // Multiply processOperator("*"); break; case 15: // Minus processOperator("-"); break; case 16: // plus processOperator("+"); break; case 17: // Backspace if (displayMode != ERROR_MODE) { setDisplayString(getDisplayString().substring(0,getDisplayString().length() - 1)); if (getDisplayString().length() < 1) setDisplayString("0"); } break; case 18: // CE clearExisting(); break; case 19: // C clearAll(); break; } } } void setDisplayString(String s) { lab1.setText(s); } String getDisplayString () { return lab1.getText(); } void addDigitToDisplay(int digit) { if (clearOnNextDigit) setDisplayString(""); String inputString = getDisplayString(); if (inputString.indexOf("0") == 0) { inputString = inputString.substring(1); } if ((!inputString.equals("0") || digit > 0) &&(inputString.length() < MAX_INPUT_LENGTH)) { setDisplayString(inputString + digit); } displayMode = INPUT_MODE; clearOnNextDigit = false; } void addDecimalPoint() { displayMode = INPUT_MODE; if (clearOnNextDigit) setDisplayString(""); String inputString = getDisplayString(); // If the input string already contains a decimal point, don't // do anything to it. if (inputString.indexOf(".") < 0) setDisplayString(new String(inputString + ".")); } void processSignChange() { if (displayMode == INPUT_MODE) { String input = getDisplayString(); if (input.length() > 0 && !input.equals("0")) { if (input.indexOf("-") == 0) setDisplayString(input.substring(1)); else setDisplayString("-" + input); } } else if (displayMode == RESULT_MODE) { double numberInDisplay = getNumberInDisplay(); if (numberInDisplay != 0) displayResult(-numberInDisplay); } } void clearAll() { setDisplayString("0"); lastOperator = "0"; lastNumber = 0; displayMode = INPUT_MODE; clearOnNextDigit = true; } void clearExisting() { setDisplayString("0"); clearOnNextDigit = true; displayMode = INPUT_MODE; } double getNumberInDisplay() { String input = lab1.getText(); return Double.parseDouble(input); } void processOperator(String op) { double numberInDisplay = getNumberInDisplay(); lastNumber = numberInDisplay; clearOnNextDigit = true; lastOperator = op; } void processEquals() { double result = 0; if (displayMode != ERROR_MODE) { try { result = processLastOperator(); displayResult(result); } catch (DivideByZeroException e) { displayError("Cannot divide by zero!"); } lastOperator = lastOperator; } } double processLastOperator() throws DivideByZeroException { double result = 0; double numberInDisplay = getNumberInDisplay(); if (lastOperator.equals("/")) { if (numberInDisplay == 0) throw (new DivideByZeroException()); result = lastNumber / numberInDisplay; } if (lastOperator.equals("*")) result = lastNumber * numberInDisplay; if (lastOperator.equals("-")) result = lastNumber - numberInDisplay; if (lastOperator.equals("+")) result = lastNumber + numberInDisplay; return result; } void displayResult(double result) { setDisplayString(Double.toString(result)); lastNumber = result; displayMode = RESULT_MODE; clearOnNextDigit = true; } void displayError(String errorMessage){ setDisplayString(errorMessage); lastNumber = 0; displayMode = ERROR_MODE; clearOnNextDigit = true; } public static void main(String arg[]) { new cal(); } }
You have used a DivideByZeroException class which is not defined. Defined that class by inheriting to Exception class
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