I. Definitions -- Please explain the following terms:

   1. abstract method (p. 795)
      A method that includes no implementation details (no method
      body) in the declaration. Abstract method declarations are
      only permitted in abstract classes.

   2. single inheritance (p. 586)
      All .NET languages only support single inheritance, which
      means that a class can extend or derive from at most one
      class. One way that languages such as C# and Java work
      around this limitation is by implementing multiple
      interfaces.

      C++ permits multiple inheritances. A C++ class can extend
      from more than one base class. This is not possible in C#,
      Java, J#, or any of the Microsoft managed .NET languages.

   3. exception (p. 799)
      An unexpected condition in a computer program that occurs
      infrequently and is usually associated with error conditions
      that cause abnormal terminations if they are not handled.

   4. stack trace (p. 806)
      A listing of all the methods that are in an execution chain
      when an exception is thrown.

      This phrase derives from the fact that, when one method
      calls (invokes) another method, the return address of the
      calling method is "pushed" onto the "stack". Then when the
      called method completes execution, the stack is "popped"
      in order to return execution back to the "next instruction"
      (i.e., to the return address) in the calling method.

      The actual parameters values for each call are usually
      stored on the stack, along with the return address.

      So, by examining the "stack" at any point in time, it is
      possible to view/determine the one (or more) methods that
      have currently called other methods, and the order of those
      calls, the corresponding actual parameter values, etc.

      This procedure is especially revealing when methods are
      called "recursively", but without proper termination, and
      then a "stack overflow" occurs. Then a stack trace can
      be very useful in analyzing and "debugging" the problem.

      Recursive calls are used heavily in "language translation",
      such as with computer language compiler software, which
      "parse" source statements and build a "parse tree" that
      represents the "meaning" of the source statements. For
      example, see Chomsky's theory of language translation,
      for Type 1 Context Sensitive Grammars (CSG), and Type 2
      Context Free Grammars (CFG), such as at 
      www.patmoss.com/pcref/chomsky.htm.

   5. finally block (p. 628-629)
      C#, like C++ and Java, handles exceptions through try...
      catch...finally blocks. Program code that may cause an
      exception is placed inside the try block. The code to
      deal with the problem (the exception handler) is placed
      in the catch block(s). And the code that we want to be
      executed whether or not an exception is thrown is placed
      in the finally block.

   6. exception handler (p. 799)
      A block of code that is executed when an exception occurs.

      where:

      exception (p. 799)
      See item 3. above.

II. Questions or short essay

    1. What is the syntax of the try...catch block? (p. 628)

       The C# try...catch...finally syntax is:

       try
       {
             // Statements
       }
       catch
       {
             // Exception handler statements
       }
       finally
       {
             // Statements
       }

    2. If you have multiple catch blocks, why is the order
       that you place them important? (p. 636-639)

       Multiple catch blocks are executed in the order in
       which they are placed in the source code. Therefore,
       they should be placed from the most specific to the
       most generic. 
       
       Because all exception classes derive from the Exception
       class, if you are including the Exception class, it
       should always be placed last.

       Because the DivideByZeroException exception derives
       from the ArithmeticException class, if both are
       included, DivideByZeroException should be placed
       before ArithmeticException.

    3. What information does the message property of an
       exception give you? (p. 632)

       The message property returns a string describing
       the exception. Since it is a property of the base
       class, it can be used with any exception object.

       The message property can be used inside a catch clause
       to display a message describing the exception.

       The object identifier e is used to name an object
       of that class. The object e may now be used with any
       of the properties or methods of the Exception class.
       
III. Programming Exercise
     Create the following programs:
     1. Create a Form that contains three Labels that hold famous
        quotes of your choice. When the program starts, the
        background color of the Form and each Label should be
        black. When the user passes a mouse over a Label, change
        its BackColor to white, revealing the text of the quote.
     2. Design and implement an application that contains GUI
        components and calculates an investment value. It should
        have text boxes that allow the user to enter the amount
        invested, the number of years for the investment, and the
        annual interest rate. When the user presses the button,
        it will accept the inputs and calculate the total value
        of the investment after the specified number of years.
        The answer should be written to a label.
     Turn in your source code for these programs.