课程作业六

package test;

import javax.swing.JOptionPane;


public class Shuru {
    double num;
    public void input(){
         try{
               String str=JOptionPane.showInputDialog("请输入成绩：");
               num=Double.parseDouble(str);
                       }
         catch(NumberFormatException e){
                        JOptionPane.showMessageDialog(null,  "输入的不是数字！",null,
                                 JOptionPane.PLAIN_MESSAGE);
                        input();
                    }
         finally{
             JOptionPane.showMessageDialog(null,  "ok！",null,
                     JOptionPane.PLAIN_MESSAGE);
         }
                   
       }
   public static void main(String args[]){
       Shuru a=new Shuru(); 
           
       while(true){
             a.input(); 
       if(a.num<=100&&a.num>=90){
           JOptionPane.showMessageDialog(null,  "成绩优秀！",null,
                     JOptionPane.PLAIN_MESSAGE);break;
       }
       else if(a.num<=89&&a.num>=80){
           JOptionPane.showMessageDialog(null,  "成绩良好！",null,
                     JOptionPane.PLAIN_MESSAGE);break;
       }
       else if(a.num<=79&&a.num>=70){
           JOptionPane.showMessageDialog(null,  "成绩中等！",null,
                     JOptionPane.PLAIN_MESSAGE);break;
       }
       else if(a.num<=69&&a.num>=60){
           JOptionPane.showMessageDialog(null,  "成绩及格！",null,
                     JOptionPane.PLAIN_MESSAGE);break;
       }
       else if(a.num<=59&&a.num>=0){
           JOptionPane.showMessageDialog(null,  "成绩不及格！",null,
                     JOptionPane.PLAIN_MESSAGE);break;
       }
       else{
           JOptionPane.showMessageDialog(null,  "输入数字超出范围！",null,
                     JOptionPane.PLAIN_MESSAGE);
       }
     }
   }
}