using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?xm) (?(DEFINE) (?<byte> 2[0-4]\d | 25[0-5] | 1\d\d | [1-9]?\d) ) ^ (10 (?:\.(?&byte)){3} | 172 \. (?: 1 [6-9] | 2\d | 3[01] ) (?:\.(?&byte)){2} | 192 \. 168 (?:\.(?&byte)){2} | ) $";
string input = @"10.0.0.0
10.1.2.3
10.255.255.255
172.16.0.0
172.25.1.2.3
172.31.255.255
12.34.56.78
123.456.789.0
192.168.0.555
192.168.0.0
192.168.1.2
192.168.255.255
";
foreach (Match m in Regex.Matches(input, pattern))
{
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