valid nya kartu credit bisa di cek

using System;
using System.Collections.Generic;
using System.Threading;

namespace CreditCardNumberGenerator
... {
   public class RandomCreditCardNumberGenerator
   {

      /*This is a port of the port of of the Javascript credit card number generator now in C#

       * by bumiayucyber http://tetsuhana90@blogspot.com
       */
/*
 * /**
* See the license below. Obviously, this is not a Javascript credit card number
* generator. However, The following class is a port of a Javascript credit card
* number generator.
*
* @author bumiayucyber
*


* Javascript credit card number generator Copyright (C) 2012 Graham King
* graham@darkcoding.net
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
* Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* www.darkcoding.net
*/
      public static String[] AMEX_PREFIX_LIST = new[] {"34", "37"};

      public static String[] DINERS_PREFIX_LIST = new[]
                                                     {
                                                        "300",
                                                        "301", "302", "303", "36", "38"
                                                     };

      public static String[] DISCOVER_PREFIX_LIST = new[] {"6011"};

      public static String[] ENROUTE_PREFIX_LIST = new[]
                                                      {
                                                         "2014",
                                                         "2149"
                                                      };

      public static String[] JCB_15_PREFIX_LIST = new[]
                                                     {
                                                        "2100",
                                                        "1800"
                                                     };

      public static String[] JCB_16_PREFIX_LIST = new[]
                                                     {
                                                        "3088",
                                                        "3096", "3112", "3158", "3337", "3528"
                                                     };

      public static String[] MASTERCARD_PREFIX_LIST = new[]
                                                         {
                                                            "51",
                                                            "52", "53", "54", "55"
                                                         };

      public static String[] VISA_PREFIX_LIST = new[]
                                                   {
                                                      "4539",
                                                      "4556", "4916", "4532", "4929", "40240071", "4485", "4716", "4"
                                                   };

      public static String[] VOYAGER_PREFIX_LIST = new[] {"8699"};

      private static String Strrev(String str)
      {
         if (str == null)
            return "";
         String revstr = "";
         for (int i = str.Length - 1; i >= 0; i--)
         {
            revstr += str[i];
         }
         return revstr;
      }

/*
* 'prefix' is the start of the CC number as a string, any number of digits.
* 'length' is the length of the CC number to generate. Typically 13 or 16
*/

      private static String completed_number(String prefix, int length)
      {
         String ccnumber = prefix;
// generate digits
         while (ccnumber.Length < (length - 1))
         {
            double rnd = (new Random().NextDouble()*1.0f - 0f);
            ccnumber += Math.Floor(rnd*10);
            Thread.Sleep(20);
         }
// reverse number and convert to int
         String reversedCCnumberString = Strrev(ccnumber);
         var reversedCCnumberList = new List<int>();
         for (int i = 0; i < reversedCCnumberString.Length; i++)
         {
            reversedCCnumberList.Add(Convert.ToInt32(reversedCCnumberString[i].ToString()));
         }
// calculate sum
         int sum = 0;
         int pos = 0;
         int[] reversedCCnumber = reversedCCnumberList
            .ToArray();
         while (pos < length - 1)
         {
            int odd = reversedCCnumber[pos]*2;
            if (odd > 9)
            {
               odd -= 9;
            }
            sum += odd;
            if (pos != (length - 2))
            {
               sum += reversedCCnumber[pos + 1];
            }
            pos += 2;
         }
// calculate check digit
         int checkdigit =
            Convert.ToInt32((Math.Floor((decimal) sum/10) + 1)*10 - sum)%10;
         ccnumber += checkdigit;
         return ccnumber;
      }

      public static String[] credit_card_number(String[] prefixList, int length,
                                                int howMany)
      {
         var result = new Stack<String>();
         for (int i = 0; i < howMany; i++)
         {
            int next = new Random().Next(0, prefixList.Length - 1);
            String ccnumber = prefixList[next - 1];
            result.Push(completed_number(ccnumber, length));
         }
         return result.ToArray();
      }

      public static String[] generateMasterCardNumbers(int howMany)
      {
         return credit_card_number(MASTERCARD_PREFIX_LIST, 16, howMany);
      }

      public static String generateMasterCardNumber()
      {
         return credit_card_number(MASTERCARD_PREFIX_LIST, 16, 1)[0];
      }

      public static string Reverse(string str)
      {
// convert the string to char array
         char[] charArray = str.ToCharArray();
         int len = str.Length - 1;
/*
now this for is a bit unconventional at first glance because there
are 2 variables that we're changing values of: i++ and len--.
the order of them is irrelevant. so basicaly we're going with i from
start to end of the array. with len we're shortening the array by one
each time. this is probably understandable.
*/
         for (int i = 0; i < len; i++, len--)
         {
/*
now this is the tricky part people that should know about it don't.
look at the table below to see what's going on exactly here.
*/
            charArray[i] ^= charArray[len];
            charArray[len] ^= charArray[i];
            charArray[i] ^= charArray[len];
         }
         return new string(charArray);
      }

      public static bool isValidCreditCardNumber(String creditCardNumber)
      {
         bool isValid = false;
         try
         {
            String reversedNumber = Reverse(creditCardNumber);
            int mod10Count = 0;
            for (int i = 0; i < reversedNumber.Length; i++)
            {
               int augend = Convert.ToInt32(reversedNumber[i]);
               if (((i + 1)%2) == 0)
               {
                  String productString = (augend*2).ToString();
                  augend = 0;
                  for (int j = 0; j < productString.Length; j++)
                  {
                     augend += Convert.ToInt32(productString[j]);
                  }
               }
               mod10Count += augend;
            }
            if ((mod10Count%10) == 0)
            {
               isValid = true;
            }
         }
         catch
         {
         }
         return isValid;
      }
   }
}