Java bluej if语句

Question

import java.util.ArrayList;

public class Lan{
    private ArrayList<Member> members;

    public Lan()
    {
        members = new ArrayList<Member>();
    }

    public void addMember(Member newMember){
        if(newMember.getBalance() >= 200)
        {
            this.members.add(newMember);
        }
        else
        {
            System.out.println("You dont have enough money to enter");
        }
    }

    public void printMembers(){
        System.out.println("People attending");
        for(Member member : members)
        {
            System.out.println(member);
        }

    }
}

public class Member{
    private String name;
    private String alias;
    private int balance;

    public Member(String fullName, String nickname){
        this.name = fullName;
        this.alias = nickname;
        this.balance = 0;
    }

    public void setBalance(int account)
    {
        if(account > 0)
        {
            balance = balance + account;
        }
        else
        {
            System.out.println("You have not entered a valid number");
        }
    }

    public String getName()
    {
        return name;
    }
    public String getAlias()
    {
        return alias;
    }

    public int getBalance()
    {
        return balance;
    }

    @Override
    public String toString() {
        return "Name: " + this.name + " / Alias: " + this.alias;
    }
}

这些是我的类Lan和Member，为了让这些成员进入局域网，他们需要有200个余额。一切正常，但我似乎不知道怎么做(Balance - 200)<；-当它们添加到Lan阵列中时，输入价格。我是否在Lan中的if语句中执行此操作？或者我需要创建一个名为cost的新字段吗

Answer 1

问题是，只有当他们有足够的钱进入时，你才想将他们的余额减少200。您可以通过在正确的if语句中将其余额设置为当前余额-200来实现这一点。像这样：

   public void addMember(Member newMember){
            if(newMember.getBalance() >= 200)
            {
                this.members.add(newMember);
newMember.setBalance(newMember.getBalance()-200);
            }
            else
            {
                System.out.println("You dont have enough money to enter");
            }
        }