Get the public ip of the user from through code

string url = "http://checkip.dyndns.org";
            System.Net.WebRequest req = System.Net.WebRequest.Create(url);
            System.Net.WebResponse resp = req.GetResponse();
            System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
            string response = sr.ReadToEnd().Trim();
            string[] a = response.Split(':');
            string a2 = a[1].Substring(1);
            string[] a3 = a2.Split('<');
            string strIpAddress = a3[0];
            return strIpAddress;