09-异常处理-成绩判断异常

源程序：
import java.util.Scanner;

public class Exam {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        boolean f=true,h=true,q=true;
        int Sc=0;
      while(f){
        System.out.println("Please input a score:");
        Scanner s=new Scanner(System.in);
        String ss=s.nextLine();
       
        int a=ss.length();
        for(int i=0;i<a;i++){
            if((ss.charAt(i)<'0')||(ss.charAt(i)>'9'))
                 break;
                
            else
                    {
                     q=false;
                     h=false;
                    }
        }
        
        
        if(q){
        try{
            throw new ScException();
        }
        catch(ScException e){
            System.out.println("格式错误");
          }
        }
        
        
       if(!h) //输入的是数字
       {
         Sc=Integer.parseInt(ss);
        if((Sc<0)||(Sc>100))
        {
            try{
                ScException x= new ScException();
                throw x;
            }
            catch(ScException x){
                System.out.println("输入异常，请输入整数");
            
                
            }
        }
        else
            f=false;
       }
       
      }
        if(Sc<60)
            System.out.println("不及格");
        else if(Sc<70)
            System.out.println("及格");
        else if(Sc<80)
            System.out.println("中");
        else if(Sc<90)
            System.out.println("良");
        else if((Sc<100)||(Sc==100))
            System.out.println("优");
            
    }

}
class ScException extends Exception{
    public ScException(){
        
    }
}