using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    private static List<string> keywords = new List<string> { "hersteller", "fabrikant" };

    private static char[] separators = new char[] { ' ', ':', '/', '\t' };

​

    public static void Main()

    {

        var texts = new List<string> {

            "Die hersteller ABCD",

            "hersteller war EFGH",

            "hersteller: IJKL",

            "Hersteller und Typ MNOP",

            "Hersteller/Typ QRST",

            "Der fabrikant UVWX",

            "fabrikant: YZAB",

            "Fabrikant und Typ CDEF",

            "Fabrikant/Typ GHIJ"

        };

​

        foreach (var text in texts)

        {

            var manufacturer = ExtractManufacturer(text);

            if (!string.IsNullOrEmpty(manufacturer))

            {

                Console.WriteLine($"Found manufacturer: {manufacturer} in \"{text}\"");

            }

            else

            {

                Console.WriteLine($"Manufacturer not found in \"{text}\"");

            }

        }

    }

​

    private static string ExtractManufacturer(string text)

    {

        text = text.ToLower(); // Normalize text to lowercase

        foreach (var keyword in keywords)

        {

            if (text.Contains(keyword))

            {

                int startIndex = text.IndexOf(keyword) + keyword.Length;

                string remainingText = text.Substring(startIndex).TrimStart(separators);

                var parts = remainingText.Split(separators, 2); // Split into at most 2 parts

                if (parts.Length > 0)

                {

                    string potentialManufacturer = parts[0];

                    if (!string.IsNullOrWhiteSpace(potentialManufacturer))

                    {

                        return potentialManufacturer;

                    }

                }

            }

        }

        return null;

    }

}

​