Final Review

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 gt last)
• result -1
• else
• interval last first
• mid1 first interval/3
• mid2 first 2interval/3
• if (target stuffmid1)
• result mid1
• else if (target stuffmid2)
• result mid2
• else if (target lt stuffmid1)
• result search(target, first, mid1-1)
• else if (target lt stuffmid2)
• result search(target, mid11, mid2-1)

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)

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 lt 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 lt 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 lt 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 lt 10) System.out.print(number)
else printDigit(number/10)
System.out.print( number10)
15
Review

• Write some Java code to compute 1 1/x 1/x2
  1/x3 ... 1/x10. 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 i0 ilt10 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 ZooAnimalnumberOfAnimals
  
• int i
• for (i 0 i lt numberOfAnimals i)
• animali new ZooAnimal()
• System.out.println("Enter data for zoo
  animal")
• animali.readInput()