IP address
using System; using System.Text.RegularExpressions; class RXassemblyApp { static void Main(string[] args) { string s = "123.45.67.89"; string e = @"([01]?\d\d?|2[0-4]\d|25[0-5])\." + @"([01]?\d\d?|2[0-4]\d|25[0-5])\." + @"([01]?\d\d?|2[0-4]\d|25[0-5])\." + @"([01]?\d\d?|2[0-4]\d|25[0-5])"; Match m = Regex.Match(s, e); Console.WriteLine("IP Address: {0}", m); for (int i = 1; i < m.Groups.Count; i++) Console.WriteLine( "\tGroup{0}={1}", i, m.Groups[i]); } }