Class GPACalculator

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----java.awt.Panel
                           |
                           +----java.applet.Applet
                                   |
                                   +----GPACalculator

public class GPACalculator
extends Applet

action(Event, Object): Performs appropriate action when button is clicked.
convert(String): Calculates the numeric grade, given the letter grade.
init(): This function is called initially, when the program begins executing.

init

 public void init()

This function is called initially, when the program begins executing. It initializes the graphics window, and sets total_grade, total_credits, and gpa to 0.

convert

 public int convert(String grade)

Calculates the numeric grade, given the letter grade.

action

 public boolean action(Event event,
                       Object arg)

Performs appropriate action when button is clicked. If the submit button is clicked, the current_grade is added to total_grade and current_credits is added to total_credits, and gpa is recalculated, and these new values are displayed on the screen. If the clear button is clicked, it sets total_credits and gpa to 0 and writes this to the screen. If the grade_choice is clicked, convert is called to convert to a number grade and stores it in current_grade. Similarly, if credit_choice is clicked, the number of credits is stored to current_credits.