using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"^((1?\d{1,2}|2([0-4]\d|5[0-5]))\.){3}(1?\d{1,2}|2([0-4]\d|5[0-5]))$|^$";
string input = @"192.168.1.1
192.168.255.255
8.8.8.8
10.10.1.1
021.8.8.8
8.021.021.8
0.0.0.0
1.0.0.0
100.10.1.1
20.200.2.2
255.255.255.254
266.274.255.0
200.249.255.8
0.0.0.0
1.0.0.0
";
RegexOptions options = RegexOptions.Multiline;
foreach (Match m in Regex.Matches(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