PhoneNumbers

StorePhoneNumbers

private static Random random = new Random(DateTime.Now.Millisecond);
        static void Main(string[] args)
        {
            string[] numbers = new string[1000000];
            string[] offsets = new string[1000000];
            for (int i = 0; i < numbers.Length; i++)
                numbers[i] = getNumber();
             
             Array.Sort(numbers);
             System.IO.File.WriteAllLines("phones.txt", numbers);

             offsets[0] = numbers[0];
             for (int i = 1; i < offsets.Length; i++)
                 offsets[i] = (long.Parse(numbers[i]) - long.Parse(numbers[i - 1])).ToString();
             System.IO.File.WriteAllLines("phonesOffsets.txt", offsets);
        }

        private static string getNumber()
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < 11; i++)
                sb.Append(random.Next(0, 9));
            return sb.ToString();
        }