using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?(DEFINE)
(?<bit>[0-1][0-9]{1,2}|2[0-4][0-9]|25[0-5])
)
(
10\.
((?&bit)\.){2}((?&bit))
)|
(
172\.
(
(1[6-9])|
(2[0-9])|
(3[0-6])
)
\.
((?&bit)\.?+){2}
)|
(
192\.168\.
((?&bit)\.?+){2}
)";
string input = @"172.31.253.126";
RegexOptions options = RegexOptions.IgnorePatternWhitespace;
Match m = Regex.Match(input, pattern, options);
Console.WriteLine("'{0}' found at index {1}", m.Value, m.Index);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx