Sha256: c5bec9d46ac2b927d68784b2bf2a68ca6452539df482069e3b09b3f122327a42
Contents?: true
Size: 1.05 KB
Versions: 332
Compression:
Stored size: 1.05 KB
Contents
using System;
using System.Linq;
public static class Luhn
{
public static bool IsValid(string number)
{
number = number.Replace(" ", "");
if (number.Length < 2 || number.Any(c => c < '0' || c > '9'))
{
return false;
}
var checksum = GenerateChecksum(number);
return checksum % 10 == 0;
}
private static int GenerateChecksum(string number)
{
var reversedIntArray = SplitToReversedIntArray(number);
for (int i = 1; i < reversedIntArray.Length; i++)
{
if (i % 2 != 0)
reversedIntArray[i] = ConvertDigitForAddend(reversedIntArray[i]);
}
Array.Reverse(reversedIntArray);
return reversedIntArray.Sum();
}
private static int[] SplitToReversedIntArray(string value)
{
return value.Select(c => int.Parse(c.ToString())).Reverse().ToArray();
}
private static int ConvertDigitForAddend(int value)
{
var doubled = value * 2;
return doubled < 10 ? doubled : doubled - 9;
}
}
Version data entries
332 entries across 332 versions & 1 rubygems