User類

package redbag;

public class User {
    private String userName;//用戶名
    private int leftMoney;//余額
//    屬性私有酷窥，提供get,set方法
    public User() {
    }

    public User(String userName, int leftMoney) {
        this.userName = userName;
        this.leftMoney = leftMoney;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public int getLeftMoney() {
        return leftMoney;
    }

    public void setLeftMoney(int leftMoney) {
        this.leftMoney = leftMoney;
    }

    public void show() {
        System.out.println("用戶" + userName + "\t"+"余額為" + leftMoney + "元");
    }
}

發(fā)包類

package redbag;

import java.util.ArrayList;

public class Manager extends User {
    public Manager() {
    }

    public Manager(String userName, int leftMoney) {
        super(userName, leftMoney);
    }

    // 發(fā)紅包
    public ArrayList<Integer> send(int totalMoney, int count){
        ArrayList<Integer> redList = new ArrayList<>();

        int leftMoney = super.getLeftMoney();
        //判斷
        if(totalMoney>leftMoney)
        {
            System.out.println("余額不足");
        }

        super.setLeftMoney(leftMoney-totalMoney);
        //每個(gè)人發(fā)的錢
        int avg = totalMoney/count;
        //除不開颅停，余出來的錢
        int mod = totalMoney%count;

        for (int i = 0; i < count-1; i++) {  //最后一個(gè)做特殊處理
            redList.add(avg);//每人分多少個(gè)
        }
        int last = avg + mod;
        redList.add(last);
        return redList;
    }
}

收包類

package redbag;

import java.util.ArrayList;
import java.util.Random;

public class Member extends User {
    public Member() {
    }

    public Member(String userName, int leftMoney) {
        super(userName, leftMoney);
    }
    //收紅包
    public void receive(ArrayList<Integer> list ){
        Random random = new Random();
        //隨機(jī)抽紅包的索引
        int index = random.nextInt(list.size());
//        Integer money = list.get(index); //查看抽的錢
        //收完之后刪除
        Integer removeMoney = list.remove(index);//拿的錢
        //更新余額
        int leftMoney = super.getLeftMoney();
        int updateMoney = leftMoney + removeMoney;
        //更新之后的錢=原來的錢+拿的錢
        super.setLeftMoney(updateMoney);
    }
}

測試

package redbag;

import java.util.ArrayList;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Manager manager = new Manager("群主",200);
        Member one = new Member("成員A",0);
        Member two = new Member("成員B",0);
        Member three = new Member("成員C",0);
        manager.show(); //為什么.show蚁堤？因?yàn)槔^承了
        one.show();
        two.show();
        three.show();
        System.out.println("請輸入金額：");
        Scanner scanner = new Scanner(System.in);
        int money = scanner.nextInt();
        System.out.println("請輸入發(fā)紅包個(gè)數(shù)：");
        int count = scanner.nextInt();
        //調(diào)用發(fā)紅包
        ArrayList<Integer> redList = manager.send(money,count);
        //調(diào)用收紅包
        one.receive(redList);//第一個(gè)人收
        two.receive(redList);
        three.receive(redList);

        manager.show();
        one.show();
        two.show();
        three.show();
    }
}

輸出

用戶群主 余額為200元
用戶成員A 余額為0元
用戶成員B 余額為0元
用戶成員C 余額為0元
請輸入金額：
50
請輸入發(fā)紅包個(gè)數(shù)：
3
用戶群主 余額為150元
用戶成員A 余額為18元
用戶成員B 余額為16元
用戶成員C 余額為16元