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// CSE 1030 - Lab 4// Nazir Nooriimport javax.swing.*;import java.awt.*;import java.awt.event.*;public class Calculator extends JFrame implements ActionListener{    public static final int WIDTH = 600;    public static final int HEIGHT = 400;        private JTextField inputA;    private JTextField inputB;    private JTextField output;        public static void main(String[] args)    {        Calculator gui = new Calculator();        gui.setVisible(true);    }        public Calculator()    {        // Frame settings        super("Java Calculator");        setSize(WIDTH, HEIGHT);        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        setLayout(new FlowLayout());                // Create panels        JPanel left = new JPanel();        JPanel right = new JPanel();        add(left);        add(right);        left.setLayout(new GridLayout(3,1));        right.setLayout(new GridLayout(4,1));                // Create text fields        inputA = new JTextField(10);        inputB = new JTextField(10);        output = new JTextField(10);        output.setEditable(false);        left.add(inputA);        left.add(inputB);        left.add(output);                // Create buttons        JButton add = new JButton("+");        JButton subtract = new JButton("-");        JButton multiply = new JButton("x");        JButton divide = new JButton("/");        right.add(add);        right.add(subtract);        right.add(multiply);        right.add(divide);        // Set button listeners        add.addActionListener(this);        subtract.addActionListener(this);        multiply.addActionListener(this);        divide.addActionListener(this);                // Create the menu bar        JMenuBar bar = new JMenuBar();        setJMenuBar(bar);                // Create menu lists        JMenu file = new JMenu("File");        JMenu clear = new JMenu("Clear");                // Create menu items        JMenuItem quit = new JMenuItem("Quit");        JMenuItem clearA = new JMenuItem("Clear A");        JMenuItem clearB = new JMenuItem("Clear B");        JMenuItem clearAll = new JMenuItem("Clear All");                // Add menu components        file.add(quit);        clear.add(clearA);        clear.add(clearB);        clear.add(clearAll);        bar.add(file);        bar.add(clear);                // Set menu action listeners        quit.addActionListener(this);        clearA.addActionListener(this);        clearB.addActionListener(this);        clearAll.addActionListener(this);    }        public void actionPerformed(ActionEvent e)    {        String action = e.getActionCommand();                if (action.equals("Quit"))            System.exit(0);        else if (action.equals("Clear A"))            inputA.setText("");        else if (action.equals("Clear B"))            inputB.setText("");        else if (action.equals("Clear All"))        {            inputA.setText("");            inputB.setText("");            output.setText("0");        }        else if (action.equals("+"))            output.setText(Double.toString(Double.valueOf(inputA.getText()) + Double.valueOf(inputB.getText())));        else if (action.equals("-"))            output.setText(Double.toString(Double.valueOf(inputA.getText()) - Double.valueOf(inputB.getText())));        else if (action.equals("x"))            output.setText(Double.toString(Double.valueOf(inputA.getText()) * Double.valueOf(inputB.getText())));        else if(action.equals("/"))        {            if (inputB.getText().equals("0") || inputB.getText().equals("0.0"))                output.setText("Error");            else                output.setText(Double.toString(Double.valueOf(inputA.getText()) / Double.valueOf(inputB.getText())));        }    }}