Tax calculator

gistfile1.cs

    public class TaxRate
    {
        public TaxRate(decimal vat, decimal limit)
        {
            Vat = vat;
            Limit = limit;
        }

        public decimal Vat { get; private set; }
        public decimal Limit { get; private set; }
    }

    public class TaxCalculator
    {
        private static IList<TaxRate> taxRates; 
        static TaxCalculator()
        {
            taxRates = new List<TaxRate>()
                           {
                               new TaxRate(10,0),
                               new TaxRate(14,5070),
                               new TaxRate(23,8660),
                               new TaxRate(30,14070),
                               new TaxRate(33,21240),
                               new TaxRate(45,40230)
                           };
        }

        public Decimal GetTaxAmount(decimal income)
        {
            decimal taxToPay = 0;
            decimal upperLimit;
            TaxRate currentRate;

            if (income<=0)
                return taxToPay;

            upperLimit = income;
            for (int i=(taxRates.Count-1); i>-1; i--)
            {
                currentRate = taxRates[i];
                if (income < currentRate.Limit)
                    continue;

                taxToPay += CalculatePercentage(upperLimit - currentRate.Limit, currentRate.Vat);
                upperLimit = currentRate.Limit;
            }

            return taxToPay;
        }
        
        private decimal CalculatePercentage(decimal number, decimal percentage)
        {
            return (number*percentage)/100;
        }
    }