project euler 13

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Numerics;

namespace Project_euler_13
{
    class Program
    {
        static void Main(string[] args)
        {
            TextReader tr = new StreamReader("tall.txt");
            int linenumber = 0;
            BigInteger[] digits = new BigInteger[101];
            BigInteger line;
            BigInteger sum = 0;
            string linje;
            if (File.Exists("tall.txt"))
            {
                //while ((line = long.Parse(tr.ReadLine())) != null)

                for (int r = 0; r <= 100; r++)
                {
                    linenumber++;
                    linje = tr.ReadLine();
                    if (linje != null)
                    {
                        digits[linenumber] = BigInteger.Parse(linje);
                    }
                }

            }
            else
            {
                File.Create("tall.txt");
            }
            Console.WriteLine("From array: ");
            for (int x = 1; x <= 100; x++)
            {
                Console.WriteLine(digits[x].ToString());
                sum += digits[x];
            }

            Console.WriteLine("\n\n");
            Console.WriteLine("Total: " + sum);
            Console.WriteLine("\nThe 10 first: "+sum.ToString().Substring(0, 10));
            Console.ReadKey();
        }
    }
}