public enum CreditCardResponse
    {
        TheWrongCardNumber,
        TheCorrectCardNumber
    }
    public class CreditCard
    {
        List<int> getOneNumbers = new List<int>();
        List<int> getTwoNumbers = new List<int>();
        List<int> getTwoNumbersTemp = new List<int>();

        public CreditCardResponse CreditCartIsValid(string cardNumber)
        {
            if (((SingleNumberTotal(cardNumber.Trim().Replace(" ", "")) + DoubleNumberTotal(cardNumber.Trim().Replace(" ", ""))) % 10) == 0)
                return CreditCardResponse.TheCorrectCardNumber;
            else
                return CreditCardResponse.TheWrongCardNumber;
        }

        private int SingleNumberTotal(string no)
        {
            int singleTotal = 0;
            for (int i = 0; i < no.Length; i++)
                if (i % 2 != 0)
                {
                    singleTotal += int.Parse(no[i].ToString());
                    getOneNumbers.Add(int.Parse(no[i].ToString()));
                }
            return singleTotal;
        }

        private int DoubleNumberTotal(string no)
        {
            for (int i = 0; i < no.Length; i++)
                if (i % 2 == 0)
                    getTwoNumbers.Add(int.Parse(no[i].ToString()) * 2);

            for (int s = 0; s < getTwoNumbers.Count; s++)
                getTwoNumbersTemp.Add(SingleNumberCount(getTwoNumbers[s]));

            return getTwoNumbersTemp.Sum();
        }

        private int SingleNumberCount(int count)
        {
            string temp = count.ToString();
            int numberTemp = 0;
            if (temp.Length > 1)
                for (int i = 0; i < temp.Length; i++)
                    numberTemp += int.Parse(temp[i].ToString());
            else
                numberTemp = count;
            return numberTemp;
        }
    }

[code:c#]            

            CreditCard card = new CreditCard();
            CreditCardResponse response = card.CreditCartIsValid("1258183272509158");