import java.util.Scanner;public class TiGaoLv {    public static void main(String[] args) {        Scanner scanner = new Scanner(System.in);        System.out.println("请输入上次成绩：");        double last = scanner.nextDouble();//        未成功写出判断用户输入数据是否合法的判断语句//        boolean q = NumberUtils.isNumber();        System.out.println("请输入本次成绩：");        double now = scanner.nextDouble();        double x = (now - last);        if (x > 0){            double y = x/last;            double z = y * 100;            System.out.println("本次成绩提高了：" + z + "%");        }else {            double y = Math.abs(x)/last;            double z = y *100;            System.out.println("本次成绩下降了：" + z + "%");        }    }}