// Exceptions demo

import javax.swing.JOptionPane;
import java.io.IOException;

public class GradeListTest
{
   public static void main(String[] args)
   {
      String gradeString = "";
      GradeList myGrades = new GradeList();
      
      while (!(gradeString.equals("-1")))
      {
        gradeString = JOptionPane.showInputDialog("Enter a grade between 0 and 100 [-1 to quit]");
        
        try
        {
        	if (!gradeString.equals("-1"))
        	{
        		try
        		{
           	 		myGrades.add(Integer.parseInt(gradeString));
           	 	}
           	 	catch (NumberFormatException e)
           	 	{
           	 		System.out.println("NumberFormatException - only numbers allowed");
           	 	}
           	 }	
        }
        catch (IllegalArgumentException exception1)
        {
            System.out.println(exception1);
        }
        catch (IllegalStateException exception2)
        {
            System.out.println(exception2);
        }
        catch (NullPointerException o)
        {
        	System.out.println("NullPointerException - only numbers allowed");
        	gradeString = JOptionPane.showInputDialog("Enter a grade between 0 and 100 [-1 to quit]");
        }
      }
      
      try
      {
            System.out.println("The grade average is " + myGrades.computeAverage());
      }
      catch (ArithmeticException exception3)
      {
            System.out.println(exception3);
      }
      
      System.exit(0);
   }
}