using System;

​

public static class Program

{

    public static void Main()

    {

        string myString = "This is STRING a222 END, and this is STRING b2838 END.";

        //Jump to starting index of `STRING`

        for (int i = myString.IndexOf("STRING"); i > 0; i = myString.IndexOf("STRING", i + 1))

        {

            //Get Index of Each END

            string a = Example.xMain();

            Jim.yMain();

            var endIndex = myString.Substring(i + "STARTING".Length).IndexOf("END");

            //PRINT substring between STRING and END of each occurance

            Console.WriteLine(myString.Substring(i + "STARTING".Length - 1, endIndex));

        }

    }

}

​

public static class Example

{

    public static string xMain()

    {

        static string Methoda()

        {

            return ("s");

        }

​

        return ("L");

    }

}

​

public static class Jim

{

    public static void yMain()

    {

        int a = 0;

        return;

    }

}