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    1. package com.atguigu.exercise6;
    2. import java.util.Scanner;
    3. import java.util.Vector;
    4. public class ScoreTest {
    5.     public static void main(String[] args) {
    6.   //1.实例化Scanner，用于从键盘获取学生成绩
    7.   Scanner scan = new Scanner(System.in);  
    9.   //2.创建Vector对象：Vector v = new Vector();相当于原来的数组
    10.   Vector v = new Vector();
    12.   //3.通过for(;;)或while(true)方式，给Vector中添加数组
    13.   int maxScore = 0;
    14.   for(;;){
    15.       System.out.println("请输入学生成绩（以负数代表结束）");
    16.       int score = scan.nextInt();
    17.       //3.2当输入是负数时，跳出循环
    18.       if(score < 0){
    19.     break;
    20.       }
    21.       if(score > 100){
    22.     System.out.println("输入的数据非法，请重新输入");
    23.     continue;
    24.       }
    25.       //3.1添加操作：v.addElement(Object obj)
    26. //      //JDK5.0之前：
    27. //      Integer inScore = new Integer(score);
    28. //      v.addElement(inScore);//多态
    30.       //JDK5.0之后：
    31.       v.addElement(score);//自动装箱
    34.       //4.获取学生成绩的最大值
    35.       if(maxScore < score){
    36.     maxScore = score;  
    37.       }
    38.   }
    40.   //5.遍历Vector，得到每个学生的成绩，并与最大成绩比较，得到每个学生的等级
    41.   char level;
    42.   for(int i = 0;i<v.size();i++){
    43.       Object obj = v.elementAt(i);
    44.       //JDK5.0之前：
    45. //      Integer inScore = (Integer)obj;
    46. //      int score = inScore.intValue();
    48.       //JDk5.0之后
    49.       int score = (int)obj;
    51.       //比较等级
    52.       if(maxScore - score <= 10){
    53.     level = 'A';  
    54.       }else if(maxScore - score <= 20){
    55.     level = 'B';
    56.       }else if(maxScore - score <= 30){
    57.     level = 'C';
    58.       }else{
    59.     level = 'D';
    60.       }
    61.       System.out.println("student-"+ i + "score is "+ score + ",level is" + level);
    62.   }
    63.     }
    64. }