小问题，可就是不明白，呵呵，菜鸟不要见怪啊。 - JAVA论坛

已结贴√ 问题点数：20 回复次数：2

小问题，可就是不明白，呵呵，菜鸟不要见怪啊。

import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class Test_ extends JFrame{
     public static void main(String arg[]){
         Test B=new Test();
         B.Fn();

     }
     void Fn(){
         String str=JOptionPane.showInputDialog("请输入你的成绩：");
         int a=Integer.parseInt(str);

         if (a>=60&&a<80)
              JOptionPane.showMessageDialog(this,"恭喜你及格了！,继续加油！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a>=80&&a<100);
          JOptionPane.showMessageDialog(this,"very good！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a<60&&a>40||a==40)
             JOptionPane.showMessageDialog(this,"you need to study hard！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a<40||a==40)
             JOptionPane.showMessageDialog(this,"hope you to have a good attitude","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a>100)
             JOptionPane.showMessageDialog(this,"error","成绩情况",JOptionPane.INFORMATION_MESSAGE);

     }


}

当我输入12时，它为什么还会弹出very good 啊？

搜索更多相关主题的帖子: void　100　public　import　

第 2 楼

得分:0

你把Fn()里的代码换成下面的代码试试：

程序代码：

void Fn(){
         String str=JOptionPane.showInputDialog("请输入你的成绩：");
         int a=Integer.parseInt(str);

         if (a>=60&&a<80)//我只改了判断条件，
              JOptionPane.showMessageDialog(this,"恭喜你及格了！,继续加油！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a>=80&&a<=100);
          JOptionPane.showMessageDialog(this,"very good！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a<60&&a>=40)
             JOptionPane.showMessageDialog(this,"you need to study hard！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a<40&&a>=0)
             JOptionPane.showMessageDialog(this,"hope you to have a good attitude","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a>100||a<0)
             JOptionPane.showMessageDialog(this,"error","成绩情况",JOptionPane.INFORMATION_MESSAGE);
        
     }

我只改了判断条件

第 3 楼

得分:20

import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class Test_ extends JFrame{//应该是Test吧？？
     public static void main(String arg[]){
         Test B=new Test();
         B.Fn();

     }
     void Fn(){
         String str=JOptionPane.showInputDialog("请输入你的成绩：");
         int a=Integer.parseInt(str);
         if (a>=60&&a<80)
              JOptionPane.showMessageDialog(this,"恭喜你及格了！,继续加油！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a>=80&&a<100);//多加了一小分号
          JOptionPane.showMessageDialog(this,"very good！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if (a<60&&a>40||a==40)
             JOptionPane.showMessageDialog(this,"you need to study hard！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a<40||a==40)
             JOptionPane.showMessageDialog(this,"hope you to have a good attitude","成绩情况",JOptionPane.INFORMATION_MESSAGE);
         if(a>100)
             JOptionPane.showMessageDialog(this,"error","成绩情况",JOptionPane.INFORMATION_MESSAGE);
     }
}
//以下我的建议，请见谅哦哦
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class Test extends JFrame{
     public static void main(String arg[]){
         Test B=new Test();
         B.Fn();

     }
     void Fn(){
         String str=JOptionPane.showInputDialog("请输入你的成绩：");
         int a=Integer.parseInt(str);

         if (a>=60&&a<80){
            JOptionPane.showMessageDialog(this,"恭喜你及格了！,继续加油！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
            }
         else if (a>=80&&a<100){
        JOptionPane.showMessageDialog(this,"very good！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
        }
         else if (a<60&&a>40){
           JOptionPane.showMessageDialog(this,"you need to study hard！","成绩情况",JOptionPane.INFORMATION_MESSAGE);
           }
         else if(a<=40&&a>=0){
           JOptionPane.showMessageDialog(this,"hope you to have a good attitude","成绩情况",JOptionPane.INFORMATION_MESSAGE);
           }
         else{
           JOptionPane.showMessageDialog(this,"error","成绩情况",JOptionPane.INFORMATION_MESSAGE);
           }

     }