using System;

using System.Text;

public class Program

{

    public static void Main(string[] args)

        {

            int result = LetsGetItDone(7);

​

            Console.WriteLine("Result is: {0}", result);

            Console.Read();

        }

​

        public static int LetsGetItDone(int limit) 

        {

            string str = GetLongString(limit);

​

            int result = 1;

            int position;

            int tempNum;

            for (int i = 0; i < limit; i++ )

            {

                position = Convert.ToInt32(Math.Pow(10, i));

                tempNum = NumAtPosition(position - 1, str);

                Console.WriteLine("At Position {0} number is {1}", position, tempNum);

                result *= tempNum;

            }

​

            return result;

        }

​

        public static string GetLongString(int limit) 

        { 

            StringBuilder str = new StringBuilder();

​

            limit = Convert.ToInt32(Math.Pow(10, limit - 1));

​

            for(int i=1; i<=limit; i++)

            {

                str.Append(i);

            }

​

            return str.ToString();

        }

​

        public static int NumAtPosition(int position, string str) 

        {

            return str[position] - '0';

        }

}