using System;

​

public class Program

{

    public static void Main()

    {

        void Log(object o) => Console.WriteLine(o);

        Log(is_valid_IP("0.0.0.0")); // should be true

        Log(is_valid_IP("1.1.1.1")); // should be true

​

    }

​

    public static bool is_valid_IP(string IpAddres)

    {

        string[] adress = IpAddres.Split('.');

        if (adress.Length != 4)

        {

            return false;

        }

​

        for (int i = 0; i < 4; i++)

        {

            int result;

            // this will erroneously reject 0.0.0.0

            if (adress[i][0] == '0') 

            {

                return false;

            }

​

            if (!int.TryParse(adress[i], out result))

            {

                return false;

            }

​

            if (result > 255)

            {

                return false;

            }

        }

​

        return true;

    }

}