java基础---22. 发红包案例

1 题目

2 思路

3 代码事项

• 用户类

public class User {
    private String name;
    private int money;

    public User() {
    }

    public User(String name, int money) {
        this.name = name;
        this.money = money;
    }

    //展示一下用户有多少钱
    public void show(){
        System.out.println("我叫:"+ name + "，我有多少钱："+ money);
    }
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getMoney() {
        return money;
    }

    public void setMoney(int money) {
        this.money = money;
    }
}

• 子类：群主类

import java.util.ArrayList;

//群主的类
public class Manager extends User {
    public Manager() {
    }

    public Manager(String name, int money) {
        super(name, money);
    }
    public ArrayList<Integer> send(int totalMoney, int count) {
        //首先需要一个集合，用来存储若干红包的金额
        ArrayList<Integer> redList = new ArrayList<>();

        //首先看下群组自己有多少钱
        int leftMoney = super.getMoney();//群主当余额
        if(totalMoney > leftMoney) {
            System.out.println("余额不足");
            return redList;
        }
        //扣钱，其实就是重新设置余额
        super.setMoney(leftMoney - totalMoney);

        //发红包需要平均拆分成为count份
        int avg = totalMoney / count;
        int mod = totalMoney % count;//余额，也就是甩下的零头

        //除不开的零头，包在最后一个红包中
        //下面把红包一个一个放到集合当中
        for(int i = 0; i < count -1; i++) {
            redList.add(avg);
        }
        //最后一个红包
        int last = avg + mod;
        redList.add(last);
        return redList;
    }
}

• 子类：普通群成员

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

//普通成员
public class Member extends User{
    public Member() {
    }

    public Member(String name, int money) {
        super(name, money);
    }
    public void receive(ArrayList<Integer> list) {
        //从多个红包中随便抽取一个给我自己
        //随机获取一个集合当中的索引编号
        int index = new Random().nextInt(list.size());
        //根据索引，从集合当中删除，并且得到被删除的红包，给自己
        int detal = list.remove(index);
        //自己本来有多少钱
        int money = super.getMoney();
        //加法，并且重新设置回去
        super.setMoney(money + detal);
    }
}

• 调用

import java.util.ArrayList;

public class MainRedPacket {
    public static void main(String[] args) {
        Manager manager = new Manager("群主",100);

        Member one = new Member("成员A",0);
        Member two = new Member("成员B",0);
        Member three = new Member("成员C",0);

        manager.show();//100
        one.show();//0
        two.show();//0
        three.show();//0

        //群众总共发20快钱，分成3个红包
        ArrayList<Integer> redList = manager.send(20,3);
        //3个成员收红包
        one.receive(redList);
        two.receive(redList);
        three.receive(redList);

        manager.show();//80
        one.show();//6
        two.show();//8
        three.show();//6

    }
}

4 若不写成继承的关系则有

• Manger类

public class Manager{
    //1
    private String name;
    private int money;

    //2
    public Manager(){

    }
    public Manager(String name, int money){
        this.name = name;
        this.money = money;
    }

    //3
    public void setName(String name){
        this.name = name;
    }
    public String getName(){
        return name;
    }
    public void setMoney(int money){
        this.money = money;
    }
    public int getMoney(){
        return money;
    }

    //4
    public void show(){
        System.out.println("我叫："+name+",我有多少钱："+money);
    }
    public ArrayList<Integer> send(int totalMoney, int count){
        ArrayList<Integer> redList = new ArrayList<>();
        int leftMoney = getMoney();
        if(totalMoney > leftMoney){
            System.out.println("余额不足");
            return redList;
        }
        setMoney(leftMoney - totalMoney);
        int avg = totalMoney / count;
        int mod = totalMoney % count;

        for(int i = 0; i < count-1; i++){
            redList.add(avg);
        }
        int last = avg + mod;
        redList.add(last);
        return redList;
    }
}

• Member类

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

public class Member{
    //1
    private String name;
    private int money;

    //2
    public Member(){

    }
    public Member(String name, int money){
        this.name = name;
        this.money = money;
    }

    //3
    public void setName(String name){
        this.name = name;
    }
    public String getName(){
        return name;
    }
    public void setMoney(int money){
        this.money = money;
    }
    public int getMoney(){
        return money;
    }

    //4
    public void show(){
        System.out.println("我叫："+name+",我有多少钱："+money);
    }
    public void receive(ArrayList<Integer> list){
        int index = new Random().nextInt(list.size());
        int detal = list.remove(index);
        int money = getMoney();
        setMoney(money + detal);
    }
}

• 调用
  import java.util.ArrayList;

public class MainRedPacket {
public static void main(String[] args) {
Manager manager = new Manager("群主",100);

    Member meb1 = new Member("成员A",0);
    Member meb2 = new Member("成员B",0);
    Member meb3 = new Member("成员C",0);

    ArrayList<Integer> redList = manager.send(20,3);
    meb1.receive(redList);
    meb2.receive(redList);
    meb3.receive(redList);

    manager.show();
    meb1.show();//6
    meb2.show();//8
    meb3.show();//6


}

}
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