自 定义线程

class  lllegalscoreException extends Exception
{
 lllegalscoreException()
 {
  
 }
 lllegalscoreException(String msg)
  {
   super(msg);
  }
}

public class score1 {

 
 public static void main(String[] args) {
  try
  {
   String level=null;
   level=scorelevel(90);
   System.out.println("90分的成绩登记为"+level);
   level=scorelevel(120);
   System.out.println("120分的成绩登记为"+level);
    }
  catch(lllegalscoreException e)
  {
   e.printStackTrace();
   
  }
                   } 
static String scorelevel(int score) throws lllegalscoreException
{
if(score>=85&&score<=100)
 return "A";
else if(score>=75&&score<85)
  return "B";
 else if(score>=60&&score<=75)
  return "C";
 else if(score<60&&score>=0)
  return "D";
 else
  throw new lllegalscoreException("非合法分数");
 
}

}