/*  Revises Example 4.2 to separate the services of the addValidScore
 *  method into getNextScore, isValid, and updateTotal methods.
 *  It is a design alternative.
 */

import javax.swing.*;

public class Zero100  {
  private int total = 0;
  private int score = 0;
  
  public void getNextScore() {            
    String input = JOptionPane.showInputDialog
                         ("Enter the score, -1 to quit");      
    score = Integer.parseInt(input);
  }
  private boolean isValid() {
    if (score >= 0 && score <= 100)
      return true;
    else
      return false;
  }
  public void updateTotal() {  
    if (isValid()) 
      total += score;
  }
  public int getTotal() {
    return total;
  }
  public static void main(String [] args) {
    Zero100 test = new Zero100();
    test.getNextScore();
    while (test.isValid()) {
       test.updateTotal();
       test.getNextScore();
    }                
    JOptionPane.showMessageDialog(null,"The total is " 
                                     + test.getTotal());
    System.exit(0);
  }
}