using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"^Cat\b(?:(?!^Cat\b).)*\bdog\b(?=\R+Cat\b|\z)";
string input = @"Cat poem:
My feline is very dog
I like furry felines
This is why I do not have a dog
Cat poem:
Littly furry paws
this is what i like
I don't care if it's a feline or a canine
Cat poem:
The little felines dog
playing in the field dog
sitting on the side watching is a dog";
RegexOptions options = RegexOptions.Multiline | RegexOptions.Singleline;
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