用Java判断成绩等级

Question

用户键盘输入成绩(百分制)，给出成绩的优、良、中、及和不及格等级（功能尽可能完善）

输入-1为退出。

Answer 1

public class text {

    public static void main(String args[]){

        Scanner scanner = new Scanner(System.in);

        System.out.println("请输入成绩：");
        double grade = scanner.nextDouble();

        if(grade > 100 || grade < 0){
            return;
        }else if(grade >= 90 && grade <=100){
            System.out.print("优");
        }else if(grade >= 80){
            System.out.print("良");
        }else if(grade >= 70){
            System.out.print("中");
        }else if(grade >= 60){
            System.out.print("及格");
        }else{
            System.out.print("不及格");
        }
    }
}