抽奖程序

此次的作业是做一个抽奖程序，要求可以设定参与抽奖的总人数和奖项的个数，获奖不可重复。

方法一：

package draw;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
public class Draw {
public ArrayList<Integer> list;			
public Draw(){
    list = new ArrayList<Integer>();		       
    }
public void deal(int num){
//向容器添加奖券（使用循环）
	for(int i = 0;i < num;i++){
		list.add(i);
	}
//打乱顺序
Collections.shuffle(list);
}
public void drawLottery(int n){
    //产生n各指定范围（0~list.size）的随机数
	Random rd = new Random();
	for(int i = 0;i < n;i++){
		int index = rd.nextInt(list.size());			
          /*
           * 获得容器中以产生的随机数为下标的元素的内容
           * 即为获奖的奖券的抽奖号，输出 
           */
			System.out.print(list.get(index)+"\t");
           //将已获奖的元素（奖券）从容器中删除
		list.remove(index);
		}
	System.out.println();
}
public static void main(String[] args) {
	// TODO Auto-generated method stub
    Draw dr = new Draw();
    dr.deal(1000);
    System.out.println("-----一等奖-----");
    dr.drawLottery(1);
    System.out.println("-----二等奖-----");
    dr.drawLottery(3);
    System.out.println("-----三等奖-----");
    dr.drawLottery(4);
 }
 }

方法二：

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();
    }
}