java__if_else 的练习

import java.util.Scanner;
public class Dome1{
    public static void main (String []args){
        Scanner input = new Scanner (System.in );
        int a,b,c,d;
        float e;
        System.out.print("请输入第一个数:");
        a= input.nextInt();
        System.out.print("请输入第二个数:");
        b= input.nextInt();
        System.out.print("请输入第三个数:");
        c= input.nextInt();
        d=a+b+c;
        e=d/3;
        if(e>100||e<0){
            System.out.print("不在范围内");
        }
        else{    
            if(e>=90&&e<=100){
                System.out.print("甲");
            }
            else if(e>=80&&e<=90){
                System.out.print("乙");
            }
            else if(e>=70&&e<=80){
                System.out.print("丙");
            }else if(e>=60&&e<=70){
                System.out.print("丁");
            }
            else{
                System.out.print("不合格");
            }
        }
        
        
        
    }
    
    
}