Exercise 2        Name __________________        Score __/24

1. (10) Sketch object diagrams for B and C similar to at right:

   1. ArrayList B = new ArrayList();
      B.add("apples");
      B.add("oranges");
      B.add("durian");
      B.remove(1);
      B.add("grapes");

   2. Use the TicketMachine definition below; a typical object diagram is at right.

      TicketMachine t1 = new TicketMachine(40);
      TicketMachine t2 = new TicketMachine(50);
      TicketMachine t3 = new TicketMachine(60);

      ArrayList C = new ArrayList();
      C.add(t1);
      C.add(t2);
      C.add(t3); 
      C.remove(0);

   public class TicketMachine  {  private int price;  private int balance;  private int total;  public TicketMachine(int ticketCost)  {        price = ticketCost;        balance = 0;        total = 0;  }  }

   
    

2. (4) From Question 1 what is:
   1. B.size()                 3
   2. C.size()                 2
   3. B.get(1)                "durian"
   4. C.get(1)               

    

3. (10) From Question 1, what is:
    
   1. int i = 0;                                0
      while (i < 5) {                        1
          System.out.println(i);         2
          i = i + 1;                           3
      }                                          4
       
   2. int i = 5;                                 5
      while (i > 0) {                         4
          System.out.println(i);          3 
          i = i - 1;                             2
      }                                            1
                                                    
   3. int i = 0;                                       "apples
      while (i < B.size() ) {                     "durian"
          System.out.println( B.get(i) );     "grapes"
          i = i + 1;
      }
       
   4. int i = B.size();                              "grapes"
      while (i > 0 ) {                              "durian"
           i = i - 1;                                   "apples"
          System.out.println( B.get(i) );
      }
       
   5. Iterator it = B.iterator();                "apples"
      while (it.hasNext() ) {                    "durians"
          System.out.println( it.next() );    "grapes"
      }