using System;

public class Program

{

    public static double MagicFunction(double s, int i)

    {

        s = s/1.1;

        Console.WriteLine(s.ToString());

        return s;

    }

    public static double Calc(double d, int i, int limit, ref double s)

    {

        if( i < limit)

        {           

            s = s + MagicFunction(d, i);

            return Calc( d /1.1, i + 1, limit, ref s);

        }

        else

            return d;

    }   

    public static void Main()

    {

        double initValue = 123.0;

        double sumSeriesReult = 0.0;

        const int limit = 10;

​

        double recursiveResult = Calc(initValue, 0, limit, ref sumSeriesReult);

        Console.WriteLine("------");

        Console.WriteLine(recursiveResult.ToString());

        Console.WriteLine(sumSeriesReult.ToString());

    }

}