What's Wrong With This Code (#19)

Monday, March 31, 2008

Leroy was shocked when the source code appeared. It was familiar yet strange, like an old lover's kiss. The code was five years old – an artifact of Leroy's first project. Leroy slowly scrolled through the code and pondered his next move. It wasn't a bug that was bothering Leroy – there were no race conditions or tricky numerical conversions. No performance problems or uncaught error conditions. It was all about design …

public class BankAccount

{

    public void Deposit(decimal amount)

    {

        _balance += amount;

        LogTransaction("Deposited {0} on {1}", amount, DateTime.Now);

    }

    public void Withdraw(decimal amount)

    {

        _balance -= amount;

        LogTransaction("Withdrew {0} on {1}", amount, DateTime.Now);

    }

    public void AccumulateInterest(decimal baseRate)

    {

        decimal interest;

        if (_balance < 10000)

        {

            interest = _balance * baseRate;

        }

        else

        {

            interest = _balance * (baseRate + 0.01);

        }

        LogTransaction("Accumulated {0} interest on {1}", interest, DateTime.Now);

    }

    void LogTransaction(string message, params object[] parameters)

    {

        using(FileStream fs = File.Open("auditlog.txt", FileMode.OpenOrCreate))

        using(StreamWriter writer = new StreamWriter(fs))

        {

            writer.WriteLine(message, parameters);

        }

    }

    public decimal Balance

    {

        get { return _balance; }

        set { _balance = value; }

    }

    decimal _balance;

}

"Times have changed, and so I have, fortunately", Leroy thought to himself. "And so will this code…"

To be continued…

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OdeToCode by K. Scott Allen