ISBN Verifier

Challenge Overview

Check if a given string is a valid ISBN-10 number.

Visit the isbn-verifier exercise on Exercism to read the full instructions and download the exercise files.

Community Solutions

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The following are the top 3 community solutions by stars:

Solution 1 by @blu-sta (⭐ 11) — View on Exercism
Solution 2 by @ErikSchierboom (⭐ 0) — View on Exercism
Solution 3 by @Muhammad-nosir (⭐ 0) — View on Exercism

Source: Exercism csharp/isbn-verifier

💡 View Solution

public static class IsbnVerifier
{
    private const string IsbnPattern = @"^\d(-?)\d{3}\1\d{5}\1[\dX]$";

    public static bool IsValid(string number)
        => IsIsbnPattern(number) && IsValidIsbnCheckSum(number);

    private static bool IsIsbnPattern(string number)
        => Regex.IsMatch(number, IsbnPattern);