Development Class C#

using System;
using System.Text.RegularExpressions;
public class EntryPoint
{
    static void Main( string[] args ) {
        // Create regex to search for IP address pattern.
        string pattern = @"
# First part match
([01]?\d\d?         
# OR
 |2[0-4]\d          
# OR
 |25[0-5])          
\.                  
# REPEAT
([01]?\d\d?|2[0-4]\d|25[0-5])\.
# REPEAT
([01]?\d\d?|2[0-4]\d|25[0-5])\.
# REPEAT
([01]?\d\d?|2[0-4]\d|25[0-5])
";
        Regex regex = new Regex( pattern,
                       RegexOptions.IgnorePatternWhitespace );
        Match match = regex.Match( "192.168.169.1" );
        while( match.Success ) {
            Console.WriteLine( "IP Address found at {0} with " +
                               "value of {1}",
                               match.Index,
                               match.Value );
            match = match.NextMatch();
        }
        
    }
}