package lianxi3;import java.util.Scanner;import java.util.Vector;public class TestScore {    public static void main(String[] args) {        // 1.从键盘输入学生成绩，输入负数结束        // 2.将学生成绩保存在Vector数组        Scanner s = new Scanner(System.in);        System.out.println("从键盘输入学生成绩，输入负数结束");        Vector v = new Vector();        int max = 0;        // while(s.nextInt()>0){        for (;;) {            int score = s.nextInt();            if (score < 0) {                break;            }            Integer score1 = score;            v.addElement(score1);            if (score > max) {                max = score;            }        }        // 3.找出最大值        System.out.println("max=" + max);        // 4.遍历Vector数组，打印学生的成绩等级        for (int i = 0; i < v.size(); i++) {            Integer in = (Integer) v.elementAt(i);            int a = in;            int degree = max - a;            char level;            if (degree <= 10) {                level = ‘A‘;            } else if (degree <= 20) {                level = ‘B‘;            } else if (degree <= 30) {                level = ‘C‘;            } else {                level = ‘D‘;            }            System.out.println("学生成绩：" + a + "成绩等级：" + level);        }    }}