Sitecore User Registration

C#

private static string Domain = "extranet";
        
public static void RegisterUser(string firstName, string lastName, string email, string password)
{
    var userName = string.Format(@"{0}\{1}", Domain, email);

    try
    {
        if (!Sitecore.Security.Accounts.User.Exists(userName))
        {
            Membership.CreateUser(userName, password, email);

            // Edit the profile information
            Sitecore.Security.Accounts.User user = Sitecore.Security.Accounts.User.FromName(userName, true);
            Sitecore.Security.UserProfile userProfile = user.Profile;
            userProfile.FullName = string.Format("{0} {1}", firstName, lastName);
        }
    }
    catch (Exception ex)
    {
        // log error
    }
}