Quiz J4-2

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Question 1

What does the program below produce for a GUI?

    // For reference
    /*        N
    *         |
    *      W--|--E
    *         |
    *         S
    */
    public static void main(final String args[]) {
        JFrame frame = new JFrame();

        JButton bOne = new JButton("1");
        JButton bTwo = new JButton("2");
        JButton bThree = new JButton("3");
        JButton bFour = new JButton("4");
        JButton bFive = new JButton("5");
        JButton bSix = new JButton("6");

        JPanel primes = new JPanel();
        JPanel composites = new JPanel();

        primes.setLayout(new BorderLayout());
        composites.setLayout(new BorderLayout());


        primes.add(bTwo, BorderLayout.EAST);
        primes.add(bThree,BorderLayout.WEST);
        primes.add(bFive,BorderLayout.NORTH);

        composites.add(bFour, BorderLayout.NORTH);
        composites.add(bSix, BorderLayout.CENTER);
 
        frame.add(primes, BorderLayout.WEST);
        frame.add(composites, BorderLayout.EAST);
        frame.add(bOne, BorderLayout.CENTER);
        frame.pack();
        frame.setTitle("Quiz J4-2");
        frame.setSize(400, 400);
        frame.setLocation(100, 100);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

Question 2

Consider the two simple math GUIs below:

class SimpleMultiplier extends JFrame{
    public SimpleMultiplier(JButton button){
        this.add(button, BorderLayout.CENTER);
        this.setTitle("Multiply");
        this.setSize(100, 100);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    public static int calculation(int a, int b){
        return a * b;
    }
}

class SimpleAdder extends JFrame {
    public SimpleAdder(JButton button){
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(calculation(4, 2));
            }
        });
        this.add(button, BorderLayout.CENTER);
        this.setTitle("Add");
        this.setSize(100, 100);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static int calculation(int a, int b){
        return a + b;
    }
}

What is the output of the below program if we click the Multiply window button?

class Main{
    public static int calculation(int a, int b){
        return a/b;
    }
    public static void main(final String args[]) {
        JButton button1 = new JButton("Calculate!");
        button1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(calculation(4, 2));
            }
        });
        JButton button2 = new JButton("Calculate!");
        SimpleMultiplier multiplier = new SimpleMultiplier(button1);
        SimpleAdder adder = new SimpleAdder(button2);
        multiplier.setVisible(true);
        adder.setVisible(true);
    }
}

Question 3

Now we run the code from question 2 again, but this time click the Add window
button. What’s the output?

Question 4

Finally we change SimpleAdder from a JFrame to a JPanel:

//                        VVVVVV Now a JPanel
class SimpleAdder extends JPanel {
    public SimpleAdder(JButton button){
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(calculation(4, 2));
            }
        });
        this.add(button, BorderLayout.CENTER);
        // ******* No more Frame setup code 
    }

    public static int calculation(int a, int b){
        return a + b;
    }
}

And run the same program from question #2, but instead adding SimpleAdder to Multiplier:

public class Main {
    public static int calculation(int a, int b){
        return a/b;
    }
    public static void main(final String args[]) {
        JButton button1 = new JButton("Calculate!");
        button1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(calculation(4, 2));
            }
        });
        JButton button2 = new JButton("Calculate!");
        SimpleMultiplier multiplier = new SimpleMultiplier(button1);
        SimpleAdder adder = new SimpleAdder(button2);
        // New Line ***********
        multiplier.add(adder,BorderLayout.WEST);
        // End New Line
        multiplier.setVisible(true);
    }
}

What’s the output if we click the SimpleAdder button?