抽奖

package homework;
import java.util.*;

public class choujiang{
private HashSet<Integer> set;
private Random rand;
private Scanner sc;

public choujiang() {
    set = new HashSet<>();
    rand = new Random();
    sc = new Scanner(System.in);
}

public void addToSet() {
    System.out.println("请输入总奖品数: ");
    int total = sc.nextInt();//total prize number
    while (set.size() < total) {
        set.add(rand.nextInt(1000));  //设置总共有多少个获奖
    }
}

public void drawPrize() {
    System.out.println("分别按顺序输入一二三等奖的获奖总数：");  
                                                            //分别设置每等奖的获奖人数
    int prize1 = sc.nextInt();//first prize number
    int prize2 = sc.nextInt();   
    int prize3 = sc.nextInt();

    Iterator iterator = set.iterator();
    int i = 0;
    System.out.println("获得一等奖的号码是 : ");
    while (i < prize1) {
        System.out.println(iterator.next());
        iterator.remove();
        i++;
    }
    i = 0;
    System.out.println("获得二等奖的号码是 :");
    while (i < prize2) {
        System.out.println(iterator.next());
        iterator.remove();
        i++;
    }
    i = 0;
    System.out.println("获得三等奖的号码是 :");
    while (i < prize3) {
        System.out.println(iterator.next());
        iterator.remove();
        i++;
    }
}

public static void main(String[] args) {
    choujiang setLearning = new choujiang();
    setLearning.addToSet();
    setLearning.drawPrize();
    }
}