如下内容段是关于C#随机生成信用卡卡号的的内容。

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

namespace CreditCardNumberGenerator
{
public class RandomCreditCardNumberGenerator
{

  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_PREFIX_LIST = new[]
             {
                "35"
             };

  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;
  }


  private static String completed_number(String prefix, int length)
  {
     String ccnumber = prefix;
     while (ccnumber.Length < (length - 1))
     {
        Thread.Sleep(20);
     }
     String reversedCCnumberString = Strrev(ccnumber);
     var reversedCCnumberList = new List<int>();
     for (int i = 0; i < reversedCCnumberString.Length; i++)
     {
        reversedCCnumberList.Add(Convert.ToInt32(reversedCCnumberString[i].ToString()));
     }
     int sum = 0;
     int pos = 0;
     int[] reversedCCnumber = reversedCCnumberList
        .ToArray();
     while (pos < length - 1)
     {
        if (odd > 9)
        {
           odd -= 9;
        }
        sum += odd;
        if (pos != (length - 2))
        {
           sum += reversedCCnumber[pos + 1];
        }
        pos += 2;
     }
     int checkdigit =
     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)
  {
     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)
           {
              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;
  }

}
}