using System;

​

public class Program

{

    public static void Main()

    {

        String St = "010003336201902121456987652358172201311010396851";

        int GTINFrom = St.IndexOf("21") + "21".Length;

        int GTINTo = St.LastIndexOf("17");

        int SFrom = St.IndexOf("01") + "01".Length;

        int STo = St.LastIndexOf("17");

        string batchValue = "";

        if (SFrom > 0 && STo > 0)

        {

            int SNF = St.IndexOf("21") + "21".Length;

            int SNT = St.LastIndexOf("17");

            if (SNF > 0 && SNT > 0)

            {

                    String resultSN = St.Substring(SNF, SNT - SNF);

            System.Console.WriteLine("Serial: " + resultSN);

            }

​

            String resultGT = St.Substring(SFrom, STo - SFrom);

            System.Console.WriteLine("GTIN: " + resultGT);

            int SNFrom = St.LastIndexOf("17") + "17".Length;

            int SNTo = St.LastIndexOf("10");

            if (SNTo > 0 && SNFrom > 0)

            {

                String result = St.Substring(SNFrom, SNTo - SNFrom);

                //System.Console.WriteLine("GTIN: " + result);

                int EFrom = St.IndexOf("01") + "01".Length;

                int EFTo = St.IndexOf("10");

                String ex = St.Substring(EFrom);

                //System.Console.WriteLine("Expiry 1: " + ex);

                int LTFrom = ex.LastIndexOf("17");

                int LTTo = ex.LastIndexOf("10");

                if (LTTo > 0 && LTFrom > 0)

                {

                    String results = ex.Substring(LTFrom, LTTo - LTFrom);

                    //System.Console.WriteLine("Expiry 2: " + results);

                    int EDFrom = results.IndexOf("17") + "17".Length;

                    int EDTo = results.IndexOf("10");

                    string ED = results.Substring(EDFrom, EDTo - EDFrom);

                    System.Console.WriteLine("Expiry: " + ED);

                    int LOTFrom = results.IndexOf("17") + "17".Length;

                    int LOTTo = results.LastIndexOf("10");

                    String result_lot = results.Substring(LOTFrom, LOTTo - LOTFrom);

                    //System.Console.WriteLine("Expiry: " + result_lot);

                    int From = St.IndexOf("17") + "17".Length;

                    int To = St.LastIndexOf("");

                    String result_batch = St.Substring(From, To - From);

                    int BatchFrom = ex.LastIndexOf("17") + "17".Length;

                    int BatchTo = ex.LastIndexOf("");

                    String batchstring = ex.Substring(BatchFrom);

                    int bF = batchstring.IndexOf("10") + "10".Length;

                    int bT = batchstring.LastIndexOf("11");

                    String bs = batchstring.Substring(bF);

                    if (bF > 0 && bT > 0)

                    {

                        int bFr = bs.LastIndexOf("11") + "11".Length;

                        int bTo = bs.IndexOf("");

                        String b = bs.Substring(bFr);

                    }

​

                    int bFr2 = ex.IndexOf("10") + "10".Length;

                    //String bs = batchstring.Substring(bF);

                    if (bFr2 > 0)

                    {

                        String b2 = ex.Substring(bFr2);

                        int bTo2 = b2.LastIndexOf("11");

                        if (bTo2 > 0)

                        {

                            int bF3 = ex.IndexOf("10") + "10".Length;

                            int bTo3 = ex.LastIndexOf("11");

                            String b3 = ex.Substring(bF3, bTo3 - bF3);

                            batchValue = b3;

                            int bf4 = b3.LastIndexOf("10") + "10".Length;

                            int bt4 = b3.LastIndexOf("");

                            if (bf4 > 0 && bt4 > 0)

                            {

                                String b4 = b3.Substring(bf4);

                                if (b4 != "")

                                {

                                    batchValue = b4;

                                }

                            }

                        }

                        else

                        {

                            batchValue = bs;

                        }

                    }

                    else

                    {

                        batchValue = bs;

                    }

                }

​

                Console.WriteLine("Batch: " + batchValue);

            }

        }

        else

        {

        }

    }

}