title: Cannot find symbol, how do you write your custom exception class
body: <p>How do you write your own custom exception class.</p>
  
  <p>I'm trying to write my own exception class that throws an InvalidTestScore.</p>
  
  <pre><code>// george beazer
  import java.util.Scanner;
  
  public class TestScores{
      public static void main(String[]args){
                  int numTests = 0;
                  double[] grade = new double[numTests];
                  double totGrades = 0;
                  double average;   
  
                  Scanner keyboard = new Scanner(System.in);
                  System.out.print("How many tests do you have? ");
  
                  numTests = keyboard.nextInt();
                  grade = new double[(int) numTests];
  
                  for (int index = 0; index &lt; grade.length; index++){
                          System.out.print("Enter grade for Test " + (index + 1) + ": ");
                          grade[index] = keyboard.nextDouble();        
  
                          if (grade[index] &lt; 0 || grade[index]&gt; 100){
                                  try {
                                    throw new InvalidTestScore();
  
                                  } catch (InvalidTestScore e) 
                                  {
  
                                      e.printStackTrace();
  
                                  }
                          }
                  }
  
  
                  for (int index = 0; index &lt; grade.length; index++){
                          totGrades += grade[index];
                  }
  
                  average = totGrades/grade.length;
                  System.out.print("The average is: " + average);
          }
  
  }
  </code></pre>