有负值的问题！ [英] Having problems with negative values!

问题描述

好的，我创建了一个类，它使用以下三个值进行操作：

Ok, I created a class which manipulates with three values like following:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Account
{
    public class Account
    {
        private double amount;
        private double drawing;
        private double deposit;
    
        public Account()
        {
        }

        public double Amount
/*This shows the amount or state of your account*/
        {
            get { return amount; }
            set { amount = value;}
        }
        
        public double Drawing
/*This presents the drawing amount form account*/
        {
            get { return drawing; }
            set { drawing = value; }
        }

        public double Deposit
/*This presents the deposit amount in account*/
        {
            get { return deposit; }
            set { deposit = value; }
        }        

    }
}

如何解决代码问题如果金额小于绘图，则允许从帐户中提取。

我可以在表单应用程序中修复它，但是如果涉及这些类，我不知道如何调用类方法以及如何修复这个在课堂上。



提前感谢您的回复。

How to resolve the code to not allow drawing from account if the amount is less than drawing.
I can fix that in a form application, but if there are involved the classes I don't know how to call class methods and how to fix this inside the class.

Thank you in advance for your reply.

推荐答案

绘图和存款应该是方法而不是属性。

一个帐户基本上持有一定数量的钱;借鉴或存入账户的方法;应该允许或不允许绘制它取决于可用的数量。

Drawing and Deposit should be methods instead of properties.
An account basically holds a given amount of money; drawing from it or depositing to it are methods on the account; drawing from it should be allowed or not depending on the available amount.

这不是很容易描述，因为你显示的代码不包含减少余额的代码，但它允许直接从账户值减去。

我可能会做的是使属性设置者私人（或可能 protected ）而不是public来防止这种情况，而是创建一个Withdraw方法 - 它可以检查并抛出异常或返回一个状态代码，上面写着不足的资金：

That's not really simple to describe, because the code you show doesn't include an code to reduce the balances, but it does allow direct subtraction from the account values.
What I would probably do is make the property setters private (or possibly protected) instead of public to prevent that, and create a Withdraw method instead - it can check and either throw an exception or return a status code which says "insufficent funds":

/// <summary>
/// This shows the amount or state of your account
/// </summary>
public double Amount
    {
    get { return amount; }
    private set { amount = value; }
    }
/// <summary>
/// This presents the drawing amount form account
/// </summary>
public double Drawing
    {
    get { return drawing; }
    private set { drawing = value; }
    }
/// <summary>
/// This presents the deposit amount in account
/// </summary>
public double Deposit
    {
    get { return deposit; }
    private set { deposit = value; }
    }
/// <summary>
/// Take the money from the account
/// </summary>
/// <param name="withdrawl"></param>
/// <returns></returns>
public bool Withdraw(double withdrawl)
    {
    if (Amount < withdrawl) return false;
    Amount -= withdrawl;
    return true;
    }

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