向银行系统添加利率和透支费

Question

这就是我想要实现的目标：

如果请求提款超过允许的透支限额（100 美元），则不会提款，并且会从余额中扣除固定的固定费用（10 美元）。

在下面的代码中，我已尽力做到这一点，但它不起作用，因为当我提取超过余额的金额时，它不会给我带来失败的交易费用，而是给我一个负余额。我也不确定当用户点击他们想要查看的帐户详细信息时，我希望它显示失败的交易费用（如果有的话）如果用户透支了。

任何帮助将不胜感激。就是想不通。

class Program
{
    class Customer
    {
        private string firstName;
        private string lastName;
        private int phoneNumber;
        private string address;

        public Customer()
        {
            firstName = "Tayla";
            lastName = "Brown";
            phoneNumber = 027493922;
            address = "55 Grey Rd";
        }

        //client info
        public string ClientInfo()
        {
            string clientinfo = ("Account Holder: " + firstName + " " + lastName + " " + "Phone Number: " + phoneNumber + " " + "Address: " + address);
            return clientinfo;
        }
    }

    class Account : Customer
    {
        // Fields

        private double accountNumber;
        protected string accountType;

        protected double balance;
        protected double deposit;
        protected double withdrawal;
        protected double interest;
        protected double fee;
        protected double overdraft;

        // Properties

        public string AccountType
        {
            get { return this.accountType; }
        }

        public double Withdrawal
        {
            get { return this.withdrawal; }
            set { this.withdrawal = value; }
        }
        public double Deposit
        {
            get { return this.deposit; }
            set { this.deposit = value; }
        }
        public double AcctNumber
        { get { return this.accountNumber; } }

        public double Bal
        { get { return this.balance; } }

        public double f
        { get { return this.fee; } }

        public double od
        { get { return this.overdraft; } }

        // Creating Random Account Number

        public virtual double AccountNumb()
        {
            Random rand = new Random();
            this.accountNumber = rand.Next(100000000, 1000000000);
            return accountNumber;
        }


        public virtual double Fee()                                                                    // Work out Fee
        {
            overdraft = 100;
            fee = 10;

            if (balance < withdrawal)
            {
                balance -= (overdraft + withdrawal);

            }
            else if (balance > withdrawal)
            {
                balance -= withdrawal;
                fee -= balance;
            }
            return balance;
        }

        //Computes General Balance(resets values)
        public virtual double Balance()
        {
            balance = balance + deposit - withdrawal;
            deposit = 0;
            withdrawal = 0;
            return balance;
        }

        //Computers Balance when withdrawal equals zero
        public virtual double DepositBalance(double input)
        {
            deposit = input;
            withdrawal = 0;
            balance = balance + deposit - withdrawal;
            return balance;
        }

        //Computers balance when deposit equals zero
        public virtual double WithBalance(double input)
        {
            withdrawal = input;
            deposit = 0;
            balance = balance + deposit - withdrawal;
            return balance;
        }

        //displays online banking menu
        public virtual void DisplayMenu()
        {
            Console.WriteLine("Welcome to your online bank account\nPlease choose from the options below: ");
            Console.WriteLine("");
            Console.WriteLine("1.View Client Info");
            Console.WriteLine("");
            Console.WriteLine("2. View Account Balance:");
            Console.WriteLine("     2A.Everyday\n     2B.Investment\n     2C.Omni");
            Console.WriteLine("");
            Console.WriteLine("3.Deposit Funds:\n     3A.Everyday\n     3B.Investment\n     3C.Omni");
            Console.WriteLine("");
            Console.WriteLine("4.Withdraw Funds:\n     4A.Everyday\n     4B.Investment\n     4C.Omni");
            Console.WriteLine("");
            Console.WriteLine("5.View Everyday Banking Details");
            Console.WriteLine("6.View Investment Banking Details");
            Console.WriteLine("7.View Omni Banking details");
            Console.WriteLine("");
            Console.WriteLine("8.Exit");
        }
    }

    // Everyday Account

    class Everyday : Account
    {
        //field

        private double minBalance;
        private double maxBalance;

        //properties
        public double MinBalance
        { get { return this.minBalance; } }

        public double MaxBalance
        { get { return this.maxBalance; } }

        //constructors

        public Everyday(double balance) : base()
        {
            this.minBalance = 0;
            this.maxBalance = 1000000000000;
            this.balance = balance;
            accountType = "Everyday Account";
        }

        //methods
    }

    // Investment Account

    class Investment : Account
    {
        //fields
        private int investmentInterest;
        private int feeInvestment;

        //properties
        public int InterestInvestment
        {
            get { return this.investmentInterest; }                                  // Sets Interest
            set { investmentInterest = 4; }
        }

        public int FeeInvestment
        {
            get { return this.feeInvestment; }                                  // Sets Fee
            set { feeInvestment = 10; }
        }

        //constructors
        public Investment(double balance) : base()
        {
            this.balance = balance;
            accountType = "Investment Account";

        }
        //methods
    }

    // Omni Account

    class Omni : Account    // If a request is made to withdraw money over and above the allowed overdraft limit, then no money is withdrawn and 
                            // a fixed flat fee is deducted from the balance
    {
        //fields
        private int interestOmni;
        private int overdraft;


        //properties
        public int InterestOmni
        {
            get { return this.interestOmni; }    // Get interest 
            set { interestOmni = 4; }
        }
        public int OverDraftOmni
        {
            get { return this.overdraft; }     // Get overdraft
        }

        //constructors
        public Omni(double balance) : base()
        {
            interestOmni = 4;
            overdraft = 1000;                         // Overdraft same as min balance?
            this.balance = balance;
            accountType = "Omni Account";

        }
    }

    static void Main(string[] args)
    {

        // Object Insantiating

        Account client = new Account(); // Our one client

        Everyday everyday = new Everyday(2000);
        everyday.AccountNumb();
        Investment investment = new Investment(500);
        investment.AccountNumb();
        Omni omni = new Omni(1000);
        omni.AccountNumb();


        string streamEverydayAccount = ("Account Number: " + everyday.AcctNumber);
        string streamInvestmentAccount = ("Account Number: " + investment.AcctNumber);
        string streamOmniAccount = ("Account Number: " + omni.AcctNumber);

        string streamClientInfo = (client.ClientInfo());

        string everydayAccountType = (everyday.AccountType);
        string investmentAccountType = (everyday.AccountType);
        string omniAccountType = (everyday.AccountType);

        // StreamWriter Everyday Account

        using (StreamWriter everydaysummary = new StreamWriter(@"EverydaySummary.txt", true))
        {
            everydaysummary.WriteLine(everydayAccountType);
            everydaysummary.WriteLine(streamClientInfo);
            everydaysummary.WriteLine(streamEverydayAccount);
        }

        // StreamWriter Investment Account

        using (StreamWriter investmentsummary = new StreamWriter(@"InvestmentSummary.txt", true))
        {
            investmentsummary.WriteLine(investmentAccountType);
            investmentsummary.WriteLine(streamClientInfo);
            investmentsummary.WriteLine(streamInvestmentAccount);
        }

        // StreamWriter Omni Account

        using (StreamWriter omnisummary = new StreamWriter(@"OmniSummary.txt", true))
        {
            omnisummary.WriteLine(omniAccountType);
            omnisummary.WriteLine(streamClientInfo);
            omnisummary.WriteLine(streamOmniAccount);
        }

        bool test = false;

        do
        {
            string everydayDepositPara = ($"Transaction: +${everyday.Deposit} at {DateTime.Now.ToString()} Current Balance: ${everyday.Bal}");
            string everdayWithdrawalPara = ($"Transaction: -${everyday.Withdrawal} at {DateTime.Now.ToString()} Current Balance: ${everyday.Bal}");
            string investmentDepositPara = ($"Transaction: +${investment.Deposit} at {DateTime.Now.ToString()} Current Balance: ${investment.Bal}");
            string investmentWithdrawalPara = ($"Transaction: -${investment.Withdrawal} at {DateTime.Now.ToString()} Current Balance: ${investment.Bal}");
            string omniDepositPara = ($"Transaction: +${omni.Deposit} at {DateTime.Now.ToString()} Current Balance: ${omni.Bal}");
            string omniWithdrawalPara = ($"Transaction: -${omni.Withdrawal} at {DateTime.Now.ToString()} Current Balance: ${omni.Bal}");

            //INSTANTIATING STREAMWRITER FILES

            // Everyday

            using (StreamWriter everdayAccountStreamSummary = new StreamWriter("EverdaySummary.txt", true))
            {
                if (everyday.Deposit > 0)
                {
                    everdayAccountStreamSummary.WriteLine(everydayDepositPara);
                    everyday.Deposit = 0;
                }
                if (everyday.Withdrawal > 0)
                {
                    everdayAccountStreamSummary.WriteLine(everdayWithdrawalPara);
                    everyday.Withdrawal = 0;
                }
            }
            //Investment

            using (StreamWriter investmentAccountStreamSummary = new StreamWriter("InvestmentSummary.txt", true))
            {
                if (investment.Deposit > 0)
                {
                    investmentAccountStreamSummary.WriteLine(investmentDepositPara);
                    investment.Deposit = 0;
                }
                if (investment.Withdrawal > 0)
                {
                    investmentAccountStreamSummary.WriteLine(investmentWithdrawalPara);
                    investment.Withdrawal = 0;
                }
            }
            //Omni

            using (StreamWriter omniAccountStreamSummary = new StreamWriter("OmniSummary.txt", true))
            {
                if (omni.Deposit > 0)
                {
                    omniAccountStreamSummary.WriteLine(omniDepositPara);
                    omni.Deposit = 0;
                }
                if (omni.Withdrawal > 0)
                {
                    omniAccountStreamSummary.WriteLine(omniWithdrawalPara);
                    omni.Withdrawal = 0;
                }
            }

            client.DisplayMenu();//the online banking menu
            string userchoice = Console.ReadLine();//user input from menu options

            switch (userchoice.ToUpper())
            {
                case "1": // Display Client Info
                    Console.Clear();
                    Console.WriteLine(client.ClientInfo());
                    break;
                case "2A": // Display Everday Account Balance
                    Console.Clear();
                    everyday.Balance();
                    Console.WriteLine("Everyday Account Balance: $" + everyday.Bal);
                    break;
                case "2B": // Display Investment Account Balance
                    Console.Clear();
                    investment.Balance();
                    Console.WriteLine("Investment Account Balance: $" + investment.Bal);
                    break;
                case "2C": // Display Omni Account Balance
                    Console.Clear();
                    omni.Balance();
                    Console.WriteLine("Omni Account Balance: $" + omni.Bal);
                    break;
                case "3A": // Everyday Account Deposit
                    Console.Clear();
                    Console.WriteLine("How much would you like to deposit?");
                    everyday.Deposit = double.Parse(Console.ReadLine());
                    Console.WriteLine("You deposited: $" + everyday.Deposit);
                    everyday.DepositBalance(everyday.Deposit);
                    break;
                case "3B":
                    Console.Clear(); // Investment Account Deposit
                    Console.WriteLine("How much would you like to deposit?");
                    investment.Deposit = double.Parse(Console.ReadLine());
                    Console.WriteLine("You deposited: $" + investment.Deposit);
                    investment.DepositBalance(investment.Deposit);
                    break;
                case "3C":
                    Console.Clear(); // Omni Account Deposit
                    Console.WriteLine("How much would you like to deposit?");
                    omni.Deposit = double.Parse(Console.ReadLine());
                    Console.WriteLine("You deposited: $" + omni.Deposit);
                    omni.DepositBalance(omni.Deposit);
                    break;
                case "4A": // Everyday account Withdrawal
                    Console.Clear();
                    Console.WriteLine("How much would you like to withdraw?");
                    everyday.Withdrawal = double.Parse(Console.ReadLine());
                    Console.WriteLine("You withdrew: $" + everyday.Withdrawal);
                    everyday.WithBalance(everyday.Withdrawal);
                    break;
                case "4B":
                    Console.Clear(); // Investment Account Withdrawal
                    Console.WriteLine("How much would you like to withdraw?");
                    investment.Withdrawal = double.Parse(Console.ReadLine());
                    Console.WriteLine("You withdrew: $" + investment.Withdrawal);
                    investment.WithBalance(investment.Withdrawal);
                    break;
                case "4C":
                    Console.Clear(); // Omni Account Withdrawal
                    Console.WriteLine("How much would you like to withdraw?");
                    omni.Withdrawal = double.Parse(Console.ReadLine());
                    Console.WriteLine("You withdrew: $" + omni.Withdrawal);
                    omni.WithBalance(omni.Withdrawal);
                    break;
                case "5":
                    Console.Clear(); // Everyday Details
                    Console.WriteLine("Everyday Banking Details");
                    everyday.Balance();
                    Console.WriteLine("Everyday Account Balance: $" + everyday.Bal);
                    break;
                case "6":
                    Console.Clear(); // Investment Details
                    Console.WriteLine("Investment Banking Details");
                    everyday.Balance();
                    Console.WriteLine("Investment Account Balance: $" + investment.Bal);                                                    // Add Interest Rate and Fee
                    Console.WriteLine("Interest Rate: " + investment.InterestInvestment + "%");
                    Console.WriteLine("Fee: "
                        );
                    break;
                case "7":
                    Console.Clear(); // Omni Details
                    Console.WriteLine("Omni Banking Details");
                    everyday.Balance();
                    Console.WriteLine("Omni Account Balance: $" + omni.Bal);
                    Console.WriteLine("Interest Rate: " + omni.InterestOmni + "%");
                    Console.WriteLine("Fee: ");
                    break;
                case "8":
                    Console.Clear(); // Exit Banking
                    Console.WriteLine("You have chosen to exit the online banking. Thanks and come again!");
                    Environment.Exit(0);
                    break;
                default: // catch all, breaks the loop
                    Console.Clear();
                    test = false;
                    break;
            }
        } while (!test);
    }
}

Answer 1

我已经对您的代码进行了重构 - 真的很难理解您想要做什么 - 所以这是一个相当大的变化。我已经删除了很多重复项，但我无法真正完成所有内容，因为您的代码中也缺少很多内容。

我无法回答如何在您的代码中修复您的一种方法，因为您在帐户类中更改状态的方式真的很难遵循。

在我的重构中，我总是像这样计算Balance：

    public decimal Balance => this.Opening + this.Deposits - this.Withdrawals + this.Interest - this.Fees;

所以现在只需正确获取Balance 的各个组件即可。

Withdraw 现在是如何做到这一点的：

    public (decimal Withdrawn, decimal Fee) Withdraw(decimal amount)
    {
        if (amount <= 0m)
        {
            throw new System.InvalidOperationException("Withdrawal amount must be positive");
        }
        decimal fee = 0;
        if (amount > this.Overdraft)
        {
            amount = 0m;
            fee = 10m;
        }
        else if (this.Balance < amount)
        {
            amount = this.Balance;
        }
        this.Withdrawals -= amount;
        return (amount, fee);
    }

如果我理解正确，当您尝试提取的金额超过Overdraft 金额时，您将获得$10 费用，并且没有任何内容被提取。我添加了一张支票，以确保您提取的金额不能超过余额。

这是我重构的其余部分。让我知道你需要讨论什么：

class Program
{
    public class Client
    {
        private string _firstName;
        private string _lastName;
        private string _phoneNumber;
        private string _address;

        public Client(string firstName, string lastName, string phoneNumber, string address)
        {
            _firstName = firstName;
            _lastName = lastName;
            _phoneNumber = phoneNumber;
            _address = address;
        }

        public string ClientInfo =>
            $"Account Holder: {_firstName} {_lastName} Phone Number: {_phoneNumber} Address: {_address}";
    }

    public abstract class Account
    {
        private Client _client;

        public Account(Client client, int accountNumber, decimal opening)
        {
            _client = client;
            this.AccountNumber = accountNumber;
            this.Opening = opening;
        }

        public Account(Client client, decimal opening) : this(client, Account.GenerateAccountNumber(), opening)
        { }

        public int AccountNumber { get; private set; }

        public string AccountType => $"{this.GetType().Name} Account";

        public abstract decimal Overdraft { get; protected set; }

        public decimal Opening { get; protected set; }
        public decimal Deposits { get; protected set; }
        public decimal Withdrawals { get; protected set; }
        public decimal Interest { get; protected set; }
        public decimal Fees { get; protected set; }

        public decimal InterestRate { get; protected set; } = 4m;

        public decimal Balance => this.Opening + this.Deposits - this.Withdrawals + this.Interest - this.Fees;

        private static Random _random = new Random();
        public static int GenerateAccountNumber() => _random.Next(100000000, 1000000000);

        public (decimal Withdrawn, decimal Fee) Withdraw(decimal amount)
        {
            if (amount <= 0m)
            {
                throw new System.InvalidOperationException("Withdrawal amount must be positive");
            }
            decimal fee = 0;
            if (amount > this.Overdraft)
            {
                amount = 0m;
                fee = 10m;
            }
            else if (this.Balance < amount)
            {
                amount = this.Balance;
            }
            this.Withdrawals += amount;
            this.Fees += fee;
            return (amount, fee);
        }

        public decimal Deposit(decimal amount)
        {
            if (amount <= 0m)
            {
                throw new System.InvalidOperationException("Deposit amount must be positive");
            }
            this.Deposits += amount;
            return amount;
        }

        public IEnumerable<string> GetTransactions()
        {
            var now = DateTime.Now;
            if (this.Deposits > 0m)
            {
                yield return $"Deposits: +${this.Deposits} at {now.ToString()} Current Balance: ${this.Balance}";
            }
            if (this.Withdrawals > 0m)
            {
                yield return $"Withdrawals: +${this.Withdrawals} at {now.ToString()} Current Balance: ${this.Balance}";
            }
        }

        public string Summary => String.Join(Environment.NewLine, this.AccountType, _client.ClientInfo, "Account Number: " + this.AccountNumber);
    }

    public class Everyday : Account
    {
        public decimal MinBalance { get; private set; } = 0m;
        public decimal MaxBalance { get; private set; } = 1000000000000m;

        public override decimal Overdraft { get; protected set; } = 100m;

        public Everyday(Client client, decimal opening) : base(client, opening)
        { }

        public Everyday(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }

    public class Investment : Account
    {
        public decimal InvestmentFee { get; private set; } = 10m;

        public override decimal Overdraft { get; protected set; } = 100m;

        public Investment(Client client, decimal opening) : base(client, opening)
        { }

        public Investment(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }

    class Omni : Account
    {
        public override decimal Overdraft { get; protected set; } = 1000m;

        public Omni(Client client, decimal opening) : base(client, opening)
        { }

        public Omni(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }

    private static void DisplayBalance(Account account)
    {
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
    }

    private static void DepositAmount(Account account)
    {
        Console.WriteLine("How much would you like to deposit?");
        decimal deposited = account.Deposit(decimal.Parse(Console.ReadLine()));
        Console.WriteLine($"You deposited: {deposited:$#,##0.00} into your {account.AccountType}");
    }

    private static void WithdrawAmount(Account account)
    {
        Console.WriteLine("How much would you like to withdraw?");
        var result = account.Withdraw(decimal.Parse(Console.ReadLine()));
        Console.WriteLine($"You withdrew: {result.Withdrawn:$#,##0.00}");
        if (result.Fee != 0m)
        {
            Console.WriteLine($"With fee: {result.Fee:$#,##0.00}");
        }
    }

    private static void DisplayDetails(Everyday account)
    {
        Console.WriteLine("Everyday Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
    }

    private static void DisplayDetails(Investment account)
    {
        Console.WriteLine("Investment Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
        Console.WriteLine("Interest Rate: " + account.InterestRate + "%");
        Console.WriteLine("Fee: ");
    }

    private static void DisplayDetails(Omni account)
    {
        Console.WriteLine("Omni Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
        Console.WriteLine("Interest Rate: " + account.InterestRate + "%");
        Console.WriteLine("Fee: ");
    }

    private static void Main(string[] args)
    {
        bool test = false;

        Client client = new Client("Tayla", "Brown", "027493922", "55 Grey Rd"); // Our one client

        Everyday everyday = new Everyday(client, Account.GenerateAccountNumber(), 2000m);
        Investment investment = new Investment(client, 500m);
        Omni omni = new Omni(client, 1000m);

        File.WriteAllText(@"EverydaySummary.txt", everyday.Summary);
        File.WriteAllText(@"InvestmentSummary.txt", investment.Summary);
        File.WriteAllText(@"OmniSummary.txt", omni.Summary);

        do
        {
            File.WriteAllLines("EverdaySummary.txt", everyday.GetTransactions());
            File.WriteAllLines("InvestmentSummary.txt", investment.GetTransactions());
            File.WriteAllLines("OmniSummary.txt", omni.GetTransactions());

            DisplayMenu();
            string userchoice = Console.ReadLine();//user input from menu options

            switch (userchoice.ToUpper())
            {
                case "1": // Display Client Info
                          //Console.Clear();
                    Console.WriteLine(client.ClientInfo);
                    break;
                case "2A": // Display Everday Account Balance
                           //Console.Clear();
                    DisplayBalance(everyday);
                    break;
                case "2B": // Display Investment Account Balance
                           //Console.Clear();
                    DisplayBalance(investment);
                    break;
                case "2C": // Display Omni Account Balance
                           //Console.Clear();
                    DisplayBalance(omni);
                    break;
                case "3A": // Everyday Account Deposit
                           //Console.Clear();
                    DepositAmount(everyday);
                    break;
                case "3B":
                    //Console.Clear(); // Investment Account Deposit
                    DepositAmount(investment);
                    break;
                case "3C":
                    //Console.Clear(); // Omni Account Deposit
                    DepositAmount(omni);
                    break;
                case "4A": // Everyday account Withdrawal
                           //Console.Clear();
                    WithdrawAmount(everyday);
                    break;
                case "4B":
                    //Console.Clear(); // Investment Account Withdrawal
                    WithdrawAmount(investment);
                    break;
                case "4C":
                    //Console.Clear(); // Omni Account Withdrawal
                    WithdrawAmount(omni);
                    break;
                case "5":
                    //Console.Clear(); // Everyday Details
                    DisplayDetails(everyday);
                    break;
                case "6":
                    //Console.Clear(); // Investment Details
                    DisplayDetails(investment);
                    break;
                case "7":
                    //Console.Clear(); // Omni Details
                    DisplayDetails(omni);
                    break;
                case "8":
                    //Console.Clear(); // Exit Banking
                    Console.WriteLine("You have chosen to exit the online banking. Thanks and come again!");
                    test = true;
                    break;
                default: // catch all, breaks the loop
                         //Console.Clear();
                    test = false;
                    break;
            }
        } while (!test);
    }

    //displays online banking menu
    private static void DisplayMenu()
    {
        Console.WriteLine("Welcome to your online bank account\nPlease choose from the options below: ");
        Console.WriteLine("");
        Console.WriteLine("1.View Client Info");
        Console.WriteLine("");
        Console.WriteLine("2. View Account Balance:");
        Console.WriteLine("     2A.Everyday\n     2B.Investment\n     2C.Omni");
        Console.WriteLine("");
        Console.WriteLine("3.Deposit Funds:\n     3A.Everyday\n     3B.Investment\n     3C.Omni");
        Console.WriteLine("");
        Console.WriteLine("4.Withdraw Funds:\n     4A.Everyday\n     4B.Investment\n     4C.Omni");
        Console.WriteLine("");
        Console.WriteLine("5.View Everyday Banking Details");
        Console.WriteLine("6.View Investment Banking Details");
        Console.WriteLine("7.View Omni Banking details");
        Console.WriteLine("");
        Console.WriteLine("8.Exit");
    }
}

---

这里有一些测试代码表明现在应该可以工作了。

private static void Main(string[] args)
{
    Client client = new Client("Tayla", "Brown", "027493922", "55 Grey Rd");
    Everyday everyday = new Everyday(client, Account.GenerateAccountNumber(), 30m);

    Console.WriteLine($"Balance: {everyday.Balance}");
    var r1 = everyday.Withdraw(15m);
    Console.WriteLine($"Withdrawn: {r1.Withdrawn}, Fee: {r1.Fee}, Balance: {everyday.Balance}");
    var r2 = everyday.Withdraw(1000m);
    Console.WriteLine($"Withdrawn: {r2.Withdrawn}, Fee: {r2.Fee}, Balance: {everyday.Balance}");
    var r3 = everyday.Withdraw(10m);
    Console.WriteLine($"Withdrawn: {r3.Withdrawn}, Fee: {r3.Fee}, Balance: {everyday.Balance}");
}

这给了：

Balance: 30
Withdrawn: 15, Fee: 0, Balance: 15
Withdrawn: 0, Fee: 10, Balance: 5
Withdrawn: 5, Fee: 0, Balance: 0

---

这是一个带有交易的版本。

class Program
{
    public class Client
    {
        private string _firstName;
        private string _lastName;
        private string _phoneNumber;
        private string _address;

        public Client(string firstName, string lastName, string phoneNumber, string address)
        {
            _firstName = firstName;
            _lastName = lastName;
            _phoneNumber = phoneNumber;
            _address = address;
        }

        public string ClientInfo =>
            $"Account Holder: {_firstName} {_lastName} Phone Number: {_phoneNumber} Address: {_address}";
    }

    public abstract class Account
    {
        private Client _client;

        public Account(Client client, int accountNumber, decimal opening)
        {
            _client = client;
            this.AccountNumber = accountNumber;
            this.Transactions.Add(Transaction.Create(DateTime.Now, opening, TransactionType.Opening));
        }

        public Account(Client client, decimal opening) : this(client, Account.GenerateAccountNumber(), opening)
        { }

        public int AccountNumber { get; private set; }

        public string AccountType => $"{this.GetType().Name} Account";

        public abstract decimal Overdraft { get; protected set; }

        public List<Transaction> Transactions { get; private set; } = new List<Transaction>();

        public decimal InterestRate { get; protected set; } = 4m;

        public decimal Balance => this.Transactions.Sum(t => t.Amount);

        private static Random _random = new Random();
        public static int GenerateAccountNumber() => _random.Next(100000000, 1000000000);

        public (decimal Withdrawn, decimal Fee) Withdraw(decimal amount)
        {
            if (amount <= 0m)
            {
                throw new System.InvalidOperationException("Withdrawal amount must be positive");
            }
            decimal fee = 0;
            if (amount > this.Overdraft)
            {
                amount = 0m;
                fee = 10m;
            }
            else if (this.Balance < amount)
            {
                amount = this.Balance;
            }
            if (amount > 0m)
            {
                this.Transactions.Add(Transaction.Create(DateTime.Now, amount, TransactionType.Withdrawal));
            }
            if (fee > 0m)
            {
                this.Transactions.Add(Transaction.Create(DateTime.Now, fee, TransactionType.Fee));
            }
            return (amount, fee);
        }

        public decimal Deposit(decimal amount)
        {
            if (amount <= 0m)
            {
                throw new System.InvalidOperationException("Deposit amount must be positive");
            }
            this.Transactions.Add(Transaction.Create(DateTime.Now, amount, TransactionType.Deposit));
            return amount;
        }

        public string Summary => String.Join(Environment.NewLine, this.AccountType, _client.ClientInfo, "Account Number: " + this.AccountNumber);
    }

    public class Everyday : Account
    {
        public decimal MinBalance { get; private set; } = 0m;
        public decimal MaxBalance { get; private set; } = 1000000000000m;

        public override decimal Overdraft { get; protected set; } = 100m;

        public Everyday(Client client, decimal opening) : base(client, opening)
        { }

        public Everyday(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }

    public class Investment : Account
    {
        public decimal InvestmentFee { get; private set; } = 10m;

        public override decimal Overdraft { get; protected set; } = 100m;

        public Investment(Client client, decimal opening) : base(client, opening)
        { }

        public Investment(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }

    class Omni : Account
    {
        public override decimal Overdraft { get; protected set; } = 1000m;

        public Omni(Client client, decimal opening) : base(client, opening)
        { }

        public Omni(Client client, int accountNumber, decimal opening) : base(client, accountNumber, opening)
        { }
    }
    
    public class Transaction
    {
        public DateTime When { get; private set; }
        public decimal Amount { get; private set; }
        public TransactionType Type { get; private set; }
        
        public static Transaction Create(DateTime when, decimal amount, TransactionType type)
        {
            if (amount <= 0m)
            {
                throw new System.InvalidOperationException("Transaction amount must be positive");
            }
            return new Transaction(when, (type == TransactionType.Withdrawal || type == TransactionType.Fee) ? -amount : amount, type);
        }
        
        private Transaction(DateTime when, decimal amount, TransactionType type)
        {
            this.When = when;
            this.Amount = amount;
            this.Type = type;
        }
    }

    public enum TransactionType { Opening, Deposit, Withdrawal, Fee, Interest }
    
    private static void DisplayBalance(Account account)
    {
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
    }

    private static void DepositAmount(Account account)
    {
        Console.WriteLine("How much would you like to deposit?");
        decimal deposited = account.Deposit(decimal.Parse(Console.ReadLine()));
        Console.WriteLine($"You deposited: {deposited:$#,##0.00} into your {account.AccountType}");
    }

    private static void WithdrawAmount(Account account)
    {
        Console.WriteLine("How much would you like to withdraw?");
        var result = account.Withdraw(decimal.Parse(Console.ReadLine()));
        Console.WriteLine($"You withdrew: {result.Withdrawn:$#,##0.00}");
        if (result.Fee != 0m)
        {
            Console.WriteLine($"With fee: {result.Fee:$#,##0.00}");
        }
    }

    private static void DisplayDetails(Everyday account)
    {
        Console.WriteLine("Everyday Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
    }

    private static void DisplayDetails(Investment account)
    {
        Console.WriteLine("Investment Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
        Console.WriteLine("Interest Rate: " + account.InterestRate + "%");
        Console.WriteLine("Fee: ");
    }

    private static void DisplayDetails(Omni account)
    {
        Console.WriteLine("Omni Banking Details");
        Console.WriteLine($"{account.AccountType} Balance: {account.Balance:$#,##0.00}");
        Console.WriteLine("Interest Rate: " + account.InterestRate + "%");
        Console.WriteLine("Fee: ");
    }

    private static void Main(string[] args)
    {
        bool test = false;

        Client client = new Client("Tayla", "Brown", "027493922", "55 Grey Rd"); // Our one client

        Everyday everyday = new Everyday(client, Account.GenerateAccountNumber(), 2000m);
        Investment investment = new Investment(client, 500m);
        Omni omni = new Omni(client, 1000m);

        File.WriteAllText(@"EverydaySummary.txt", everyday.Summary);
        File.WriteAllText(@"InvestmentSummary.txt", investment.Summary);
        File.WriteAllText(@"OmniSummary.txt", omni.Summary);

        do
        {
            File.WriteAllLines("EverdaySummary.txt", everyday.Transactions.Select(t => $"{t.When} {t.Type} {t.Amount}"));
            File.WriteAllLines("InvestmentSummary.txt", investment.Transactions.Select(t => $"{t.When} {t.Type} {t.Amount}"));
            File.WriteAllLines("OmniSummary.txt", omni.Transactions.Select(t => $"{t.When} {t.Type} {t.Amount}"));

            DisplayMenu();
            string userchoice = Console.ReadLine();//user input from menu options

            switch (userchoice.ToUpper())
            {
                case "1": // Display Client Info
                          //Console.Clear();
                    Console.WriteLine(client.ClientInfo);
                    break;
                case "2A": // Display Everday Account Balance
                           //Console.Clear();
                    DisplayBalance(everyday);
                    break;
                case "2B": // Display Investment Account Balance
                           //Console.Clear();
                    DisplayBalance(investment);
                    break;
                case "2C": // Display Omni Account Balance
                           //Console.Clear();
                    DisplayBalance(omni);
                    break;
                case "3A": // Everyday Account Deposit
                           //Console.Clear();
                    DepositAmount(everyday);
                    break;
                case "3B":
                    //Console.Clear(); // Investment Account Deposit
                    DepositAmount(investment);
                    break;
                case "3C":
                    //Console.Clear(); // Omni Account Deposit
                    DepositAmount(omni);
                    break;
                case "4A": // Everyday account Withdrawal
                           //Console.Clear();
                    WithdrawAmount(everyday);
                    break;
                case "4B":
                    //Console.Clear(); // Investment Account Withdrawal
                    WithdrawAmount(investment);
                    break;
                case "4C":
                    //Console.Clear(); // Omni Account Withdrawal
                    WithdrawAmount(omni);
                    break;
                case "5":
                    //Console.Clear(); // Everyday Details
                    DisplayDetails(everyday);
                    break;
                case "6":
                    //Console.Clear(); // Investment Details
                    DisplayDetails(investment);
                    break;
                case "7":
                    //Console.Clear(); // Omni Details
                    DisplayDetails(omni);
                    break;
                case "8":
                    //Console.Clear(); // Exit Banking
                    Console.WriteLine("You have chosen to exit the online banking. Thanks and come again!");
                    test = true;
                    break;
                default: // catch all, breaks the loop
                         //Console.Clear();
                    test = false;
                    break;
            }
        } while (!test);
    }

    //displays online banking menu
    private static void DisplayMenu()
    {
        Console.WriteLine("Welcome to your online bank account\nPlease choose from the options below: ");
        Console.WriteLine("");
        Console.WriteLine("1.View Client Info");
        Console.WriteLine("");
        Console.WriteLine("2. View Account Balance:");
        Console.WriteLine("     2A.Everyday\n     2B.Investment\n     2C.Omni");
        Console.WriteLine("");
        Console.WriteLine("3.Deposit Funds:\n     3A.Everyday\n     3B.Investment\n     3C.Omni");
        Console.WriteLine("");
        Console.WriteLine("4.Withdraw Funds:\n     4A.Everyday\n     4B.Investment\n     4C.Omni");
        Console.WriteLine("");
        Console.WriteLine("5.View Everyday Banking Details");
        Console.WriteLine("6.View Investment Banking Details");
        Console.WriteLine("7.View Omni Banking details");
        Console.WriteLine("");
        Console.WriteLine("8.Exit");
    }
}