Exercise 3        Name __________________        Score __/20

1. (4) Give the object diagram for the following fixed size array declarations similar to a right for: int [] hours = int[24];

   1. int [ ] A;
      A = new int [ 4 ];

   2. boolean [ ] B;
      B = new boolean [ 3 ];
      
       

   public class NumberDisplay  {  private int limit;  private int value;   public NumberDisplay(int rollOverLimit)  {      limit = rollOverLimit;      value = 0;  }   public int getValue()  {      return value;  }   public void setValue(int replacementValue)  {      if((replacementValue >= 0) && (replacementValue < limit))           value = replacementValue;  }   public void increment()  {      value = (value + 1) % limit;  }  }

    

2. (3) Give the object diagram for the following fixed size array declaration similar to that of the TicketMachine at right.

   Use the NumberDisplay definition.

   NumberDisplay [ ] nd;
   nd = new NumberDisplay [ 2 ];

3. (4) From Question 1 add the following assignments to the object diagram:
   1. A
      • variable 0 the value -2
      • variable 1 the value -3
      • variable 2 the value -7
      • variable 3 the value -5
   2. B
      1. variable 0 the value true
      2. variable 1 the value false
      3. variable 2 the value true
          
4. (3) From Question 3, what is:
    
   1. for (int i = 0; i < 4; i++)
          System.out.println(A [ i ] );
       
   2. for (int i = 3; i > 0; i--)
          System.out.println(A [ i ] );
       
   3. for (int i = 0; i < 4; i++)
          System.out.println(B [ i ] );
       
   4. int sum = 0;
      for (int i = 0; i < 4; i++)
          sum = A [ i ] + sum;
      System.out.println( sum );
       
   5. boolean sum = true;
      for (int i = 0; i < 3; i++)
          sum = B [ i ] && sum;
      System.out.println( sum );
       
5. (5) Add to the object diagram of Question 2 the results of the following similar to that at right for the TicketMachine example in Chapter 4 notes:

   NumberDisplay [ ] nd;
   nd = new NumberDisplay [ 2 ];

   nd[ 0 ] = new NumberDisplay( 10 );
   nd[ 1 ] = new NumberDisplay( 24 );
   
   nd[ 0 ].increment();
   nd[ 1 ].setValue( 20 );

6. (1) Continuing Question 5, what is:

   nd[ 1 ].getDisplayValue( );