using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"^(?:(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)\.){3}(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)$";
string input = @"// Accept ✅
127.0.0.1
192.168.1.1
192.168.1.255
255.255.255.255
0.0.0.0
// Reject ❌
033.33.33.33
127.1
192.168.1.256
-1.2.3.4
1.1.1.1.";
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