Assignment

The assignment is to implement exceptions for division by zero in the calculator of HW6. The assignment consists of two parts:

1. Define an exception class and modify the Calculator class. 

• Define a new class divideException that extends the Exception class similar to the counterException class defining:
  • a constructor that initializes a string field for an instance of a divideException,
  • a method toString that returns the string field.
• Modify Homework 6, the Calculator class:
  • throw the divideException when the divisor is zero,
  • on a divideException:
    • print a message to the console using System.out.println that includes the exception parameter as a string,
    • display on the calculator an error message using the updateDisplay method,
    • print the stack trace of executions to the console,
    • return at the end of the catch
• Test in appletviewer:
  • using the Calculator class on division by zero,
  • using the Scientific class on division by zero.
• Print
  • Program listing of Calculator and divideException class definition.
  • Command prompt window showing messages for Calculator and Scientific calculator.
  • Applet window showing messages for Calculator and Scientific calculator.

2. Modify Calculator class and UserInterface class.

• Modify the Calculator onClick method to:
  • rethrow the divideException,
  • print the stack trace of executions to the console,
• Make any modifications to UserInterface class methods needed to accommodate the previous modification. Print a message and the exception parameter where the exception is handled.
• Test in appletviewer:
  • using the Calculator class on division by zero.
• Print
  • Program listing of Calculator and UserInterface class definition.
  • Command prompt window showing messages for Calculator and UserInterface classes.
  • Applet window showing messages for Calculator.

Turn in

• Cover sheet with your name, date, and Homework 8.
• Printouts for parts 1 and 2.