1. Final Review

2. Review A Binary Search divides a sorted data structure into two equal parts and each time throws away the part that cannot contain the item of interest. A Tertiary Search divides a sorted data structure into three equal parts and each time throws away the two parts that cannot contain the item of interest. Write a recursive method with the signature private int search (int target, int first, int last) that performs a Tertiary Search on an integer array named stuff (which is a class variable).

3. private int search (int target, int first, int last) { int result = -1; int mid1, mid2, interval; if (first > last) result = -1; else { interval = last – first; mid1 = first + interval/3; mid2 = first + 2*interval/3; if (target == stuff[mid1]) result = mid1; else if (target == stuff[mid2]) result = mid2; else if (target < stuff[mid1]) result = search(target, first, mid1-1); else if (target < stuff[mid2]) result = search(target, mid1+1, mid2-1); else result = search(target, mid2+1, last); } return result; }

4. Review Create a class that extends JFrame to display a window like this: Before the user clicks OK for the first time, the bottom third of the window contains no text (ie. it does not say “Hello..”) After the user clicks OK, the bottom third displays “Hello” plus the name the user entered.

5. import javax.swing.*; import java.awt.*; import java.awt.event.*; public class FinalQuestion extends JFrame implements ActionListener { public static final int WIDTH = 400; public static final int HEIGHT = 200; JPanel namePanel; JLabel nameLabel; JTextField nameText; JTextField helloText; JButton helloButton;

6. FinalQuestion() { setSize(WIDTH,HEIGHT); Container contentPane = getContentPane(); contentPane.setLayout(new GridLayout(3,1)); namePanel = new JPanel(); namePanel.setLayout(new FlowLayout()); nameText = new JTextField(20); nameLabel = new JLabel("Enter your name:"); namePanel.add(nameLabel); namePanel.add(nameText); helloText = new JTextField(20); helloText.setText(""); helloText.setEditable(false); helloButton = new JButton("OK"); helloButton.addActionListener(this); contentPane.add(namePanel); contentPane.add(helloButton); contentPane.add(helloText); }

7. public void actionPerformed (ActionEvent e) { if (e.getActionCommand().equals("OK")) { helloText.setText ("Hello " + nameText.getText() + "!"); } public static void main(String[] args) { FinalQuestion f = new FinalQuestion(); f.setVisible(true); } } // end class

8. Review Write a method called average which takes as parameters an int array a and an int numValues. If numValues is less than or equal to zero, throw a DivideByZeroException with a message that says “Error”. Catch the exception inside the average method, print out the message, and return zero. If no exception is thrown, call a method called sumArray which takes as parameters an int array and an int representing the number of values to average. Divide this sum by numValues to get the average. Return the average as a double.

9. Review public double average (int[] a, int numValues) { try { if (numValues <= 0) throw new DivideByZeroException(“Error”); int sum = sumArray (a, numValues); return sum / numValues; } catch (DivideByZeroException e) { System.out.println(e.getMessage()); return 0; }

10. Review Modify the method average so that the method throws a DivideByZeroException containing the message “Error” if numValues <= 0. The calling method must handle the exception. If no exception is thrown, calculate and return the average as in the previous question.

11. Review public double average (int[] a, int numValues) throws DivideByZeroException { if (numValues <= 0) throw new DivideByZeroException(“Error”); int sum = sumArray (a, numValues); return sum / numValues; }

12. Review Given a ListNode class with the following methods: void setData(String x) String getData() void setLink (ListNode l) ListNode getLink() And a LinkedList class with the following class variables: private ListNode head; private ListNode current; Write a LinkedList method with the signature public void insertNode(String newData) that (1) creates a new ListNode, (2) puts newData into it, (3) inserts the new ListNode right after the node pointed to by current. Assume that the class variables in ListNode are private, so you will have to call setData, getData, etc, methods.

13. Review public void insertNode (String newData) { ListNode newNode = new ListNode(); newNode.setData(newData); newNode.setLink(current.getLink()); current.setLink(newNode); }

14. Review Write a recursive method to display an integer number with embedded blanks. For example, if the number is 285, your method should print “2 8 5”. static void printDigits(int number) { if (number < 10) System.out.print(number); else { printDigit(number/10); System.out.print(“ “ + number%10); }

15. Review Write some Java code to compute 1 + 1/x + 1/x 2 + 1/x 3 +... + 1/x 10. Assume that x is already declared and initialized. Use a loop and do not use any function in the Math class. double result = 1.0; double value = 1.0; for (int i=0; i<=10; i++) { value /= x; result += value; }

16. Review Write a code fragment to ask the user to "Enter number of zoo animals". Store that in the integer variable numberOfAnimals. Use that variable to declare an array of ZooAnimal class objects. Write a for loop to iterate through each of those objects: Declare each one, prompt the user to "Enter data for zoo animal", and then use the ZooAnimal method readInput() to read that data. You can assume a Scanner object called keyboard is already declared.

17. Review System.out.println("Enter number of zoo animals"); numberOfAnimals = keyboard.nextInt(); ZooAnimal[] animal = new ZooAnimal[numberOfAnimals]; int i; for (i = 0; i < numberOfAnimals; i++) { animal[i] = new ZooAnimal(); System.out.println("Enter data for zoo animal"); animal[i].readInput(); }