using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string[] versionStrings = new [] {"3.5.25569", "2.5.25557", "2.5.25580", "2.5.25569", "2.4.25569"};

        IEnumerable<VersionNumber> versions = versionStrings.Select(s => VersionNumber.Parse(s));

        IOrderedEnumerable<VersionNumber> sorted = versions.OrderBy(v => v);

        foreach (var res in sorted) {

            Console.WriteLine(res); 

        }

    }

}

​

​

public class VersionNumber : IComparable {

​

    public int Major    { get; set; }

    public int Minor    { get; set; }

    public int Revision { get; set; }

​

    // Converts string to VersionNumber object

    public static VersionNumber Parse(string s) {

        if (string.IsNullOrWhiteSpace(s)) {

            throw new ArgumentNullException();

        }

        var result = new VersionNumber();

​

        var parts = s.Split(new [] {'.'});

        if (parts.Count() != 3) {

            throw new ArgumentException("Input string must be in format 'X.Y.ZZZZZ'.");

        }

​

        try {

            result.Major = int.Parse(parts[0]);

            result.Minor = int.Parse(parts[1]);

            result.Revision = int.Parse(parts[2]);

        }

        catch (FormatException) {

            throw new ArgumentException("Input string must be in format 'X.Y.ZZZZZ', with X, Y, Z integers.");

        }

        return result;

    }

​

    // Compares two VersionNumbers

    public int CompareTo(object obj) {

        if (obj == null) return 1;

​

        VersionNumber otherVersion = obj as VersionNumber;

        if (otherVersion == null) {

            throw new ArgumentException("Object is not a VersionNumber");

        }

​

        // start comparison with Major Version, then Minor, then Revision

        var result = Major.CompareTo(otherVersion.Major);

        if (result == 0) {

            result = Minor.CompareTo(otherVersion.Minor);

        }

        if (result == 0) {

            result = Revision.CompareTo(otherVersion.Revision);

        }

        return result;

    }

    public override string ToString() {

        return Major + "." + Minor + "." + Revision;

    }

}