ANSWERS FOR PRACTICE MIDTERM A

1.a. The Java compiler takes the Java source code and converts it into
     binary Byte Code.  This Byte Code is more efficient to run than
     source code and can be executed on any machine for which a Java
     interpreter is available.

1.b. Structured programming is the idea that all programs can be written
     using three constructions: sequence, decision (if..else), and repetition
     (while).  No go to statements are needed, which makes the code much
     easier to understand.

1.c. The address of a variable is the actual location in the computers memory
     where the value of the variable is stored.

1.d. An assignment operator is an operator that changes the value of a variable
     by assigning a new value to it.  This new value can be independent of the
     original value as in the case of =, or the new value can depend on the
     original value as in the case of +=, -=, *=, /=, %=, ++, --.

2. When you run this Java program, the loop continues forever.  It turns out that
   Java does not check for overflow in integers; the high order bits are just lost,
   much like when an odometer rolls over to 100,000 miles: it goes back to 0.  When
   the "binary odometer" of a Java 4-byte int gets set to 4,294,967,296, which is
   1 00000000 00000000 00000000 00000000 in binary, it rolls over to 0.  This is
   because an int can only hold 32 bits.  The 33rd leftmost bit is lost.

   As a result, the values printed are
   2
   4
   16
   256
   65536
   0
   0
   0
   .....


3. 

public class Main
{
    public static void main(String[] args)
    {
        String word;
        char letter;
        int i, vowelCount = 0;
  
        word = JOptionPane.showInputDialog("Enter a string."));
        word = word.toUpperCase();
        for(i = 0; i <= word.length() - 1; i++)
        {
            letter = word.charAt(i);
            if(letter=='A' || letter=='E' || letter=='I' || 
               letter=='O' || letter=='U')
            {
                vowelCount++; 
            }
        }
        System.out.println("The number of vowels is " + 
            vowelCount + ".");
    }
}

4.

public class Main
{
    public static void main(String[] args)
    {
        int a, b, c, d, s, t, result;

        a = Integer.parseInt(
            JOptionPane.showInputDialog("Enter an int."));
        b = Integer.parseInt(
            JOptionPane.showInputDialog("Enter an int."));
        c = Integer.parseInt(
            JOptionPane.showInputDialog("Enter an int."));
        d = Integer.parseInt(
            JOptionPane.showInputDialog("Enter an int."));

        s = Math.min(a, b);
        t = Math.min(c, d);
        result = Math.min(s, t);
        System.out.println("The minimum is " + result + ".");

        s = Math.max(a, b);
        t = Math.max(c, d);
        result = Math.max(s, t);
        System.out.println("The maximum is " + result + ".");
    }
}