CSC 211 -- ANSWERS FOR PRACTICE FINAL A

Warning, the code is not tested to look out for minor typos.

1.    s.a     s.b     t.a      t.b     u.a     u.b      Output:
   --------+-------+-------+---------+------+---------  17 xyz
       11    "xyz"    100   "apple3"    11   "7peach5"  100 apple38
       17    "xyz"    100   "apple38"   11   "7peach5"  11 7peach5

2. a. See notes.
   b. Long version.
   public static void main(String[] args)
   {
       int x, y, result;
       FileReader fr = new FileReader("c:\\numbers.txt");
       BufferedReader br = new BufferedReader(fr);
       x = Integer.parseInt(br.readLine());
       y = Integer.parseInt(br.readLine());
       result = x + y;
       System.out.println(result);
   }

   b. Short (macho) version.
   public static void main(String[] args)
   {
       FileReader fr = new FileReader("c:\\numbers.txt");
       BufferedReader br = new BufferedReader(fr);
       System.out.println(Integer.parseInt(br.readLine()) +
                          Integer.parseInt(br.readLine()));
   }

   c. Long version
   public static void main(String[] args)
   {
       int x, y, result;
       x = Integer.parseInt(args[0]);
       y = Integer.parseInt(args[1]);
       result = x + y;
       System.out.println(result);
   }

   c. Short (macho) version
   public static void main(String[] args)
   {
       System.out.println(Integer.parseInt(args[0]) +
       			  Integer.parseInt(args[1]));
   }

3. a. Example Instance variables: departureDateAndTime, 
          arrivalDataAndTime, maxPassengers, numbPassengers, 
          orig, dest.
      Example Methods: Constructor, toString, getOrig, getDest, 
          addPassenger, removePassenger.

   b.
   public class AirlineFlight
   {
       private int maxPassengers, numbPassengers;
       private String orig, dest;

       public AirlineFlight(String anOrig, String aDest)
       {
           maxPassengers = 0;
           numbPassengers = 0;
           orig = anOrig;
           dest = aDest;
       }

       public String toString()
       {
           return "Max=" + maxPassengers + " N=" + numbPassengers +
                  " Orig=" + orig + " Dest=" + dest;
       }

       public void getOrig()
       {
           return orig;
       }

       public void getDest()
       {
           return dest;
       }

       public void addPassenger()
       {
           numbPassengers++;
       }

       public void removePassenger()
       {
           numbPassengers--;
       }
   }

   c.  Test the AirlineFlight class.
   public static void main(String[] args)
   {
       AirlineFlight x = new AirlineFlight("ORD", "SAN");
       System.out.println(x.getOrig());
       System.out.println(x.getDest());
       System.out.println(x);
   }

   d. Assume an array of AirlineFlight objects a that is already
      read in from a file.  Assume that there are no unused slots
      in the array.  This part is considered to hard to be on
      the final exam.  ORD is the 3 letter abbreviation for Chicago
      O'Hare and SAN is the abbreviation for San Diego.

   public static void main(String[] args)
   {
       ...
       int i, j;
       for(i = 0; i <= a.length - 1; i++)
            for(j = 0; j <= a.length - 1; j++)
                if(a[i].getOrig().equals("ORD") &&
                   a[j].getDest().equals("SAN") &&
                   a[i].getDest().equals(a[j].getOrig()))
                       System.out.println(
                           "Orig=ORD  Middle= " + 
                           a[i].getDest() + 
                           " Dest=SAN");
   }

   3. 
   public class Die
   {
       private int face;

       public Die()
       {
           roll();
       }

       public void roll()
       {
           return (int)(Math.random() * 6) + 1;
       }

       public int getFace()
       {
           return face;
       }
   }

   public class Main
   {
       public static void main(String[] args)
       {
           Die x = new Die();
           int[] total = new int[7];
           int i;

           for(i = 1; i <= 100; i++)
           {
               x.roll();
               total[x.getFace()]++;
           }

           for(i = 1; i <= 6; i++)
               System.out.println("Face " + i + ": " + total[i]);
       }
   }
   
 5. The import statements are omitted.
    The main statement is the same for both Problems 5 and 6:
    
public class Main
{
    public static void main(String[] args)
    {
        UI x = new UI();
    }
}

public class UI extends JFrame
{
    JTextField t;
    JButton b;
    JPanel p;
    ClickDetector cd;

    public UI()
    {
        super("To Upper");
        t = new JTextField(5);
        b = new JButton("To Upper");
        p = new JPanel();
        cd = new ClickDetector();
        p.add(t);
        p.add(b);
        setContentPane(p);
        b.addActionListener(cd);
        setSize(150, 100);
        show();
    }

    private class ClickDetector implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
	    t.setText(t.getText().toUpperCase());
        }
    }
}

6.
public class UI extends JFrame
{
    JTextField[] t;
    JButton b;
    JPanel p;
    ClickDetector cd;

    public UI()
    {
        super("To Upper");
        int i;
        t = new JTextField[6];
        for(i = 0; i <= 5; i++)
            t[i] = new JTextField(10);
        b = new JButton("Average");
        p = new JPanel();
        cd = new ClickDetector();
        p.add(t);
        p.add(b);
        setContentPane(p);
        b.addActionListener(cd);
        setSize(150, 300);
        show();
    }

    private class ClickDetector implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            int i, sum = 0;
            double ave;
            for(i = 0; i <= 4; i++)
                sum += t[i].getText().length();
            ave = sum / 5.0;
	    t[5].setText(String.valueOf(ave));
        }
    }
}