public class Grade {

   public static void main (String[] p) {
      double percent;
      while (true) {
         System.out.print ("Input percentage: ");
         percent = TextIO.getlnDouble();
         System.out.print (percent + ": ");
         System.out.println (grade (percent));
      } // while
   } // main


   public static String grade (double d) {
      String grade = "not defined";
      if ((d > 100.)||(d < 0.))
         throw new RuntimeException ("Illegal percent");
      if (d <= 50.) grade = "fail";
      else if (d <= 60.) grade = "sufficient";
      else if (d <= 70.) grade = "satisfactory";
      else if (d <= 80.) grade = "good";
      else if (d <= 90.) grade = "very good";
      else if (d <= 100.) grade = "excellent";
      else grade = "undefined";
      return grade;
   }
}