C#-Code

namespace IPadresse
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Type IP-adress: ");
            string ip = Convert.ToString(Console.ReadLine());
            Console.WriteLine(IsIP(ip));
            Console.ReadLine();
            
        }

        static bool IsIP(string IP)
        {
            return System.Text.RegularExpressions.Regex.IsMatch(IP, @"\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$\b");
        }
    }
}