CalcSumAndAverageOfSequence

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

class CalcSumAndAverageOfSequence
{
    // Write a program that reads from the console a sequence of positive integer numbers.
    // The sequence ends when empty line is entered. Calculate and print the sum and average of the elements of the sequence.
    // Keep the sequence in List<int>.

    private static void AddNumber(string inputLine, ref List<int> numsList)
    {
        //asume substring of digits is valid number

        StringBuilder numSB = new StringBuilder();

        for (int i = 0; i < inputLine.Length; i++)
        {
            char currentChar = inputLine[i];

            if (char.IsDigit(currentChar))
            {
                numSB.Append(currentChar);
            }
            else
            {
                if (!string.IsNullOrEmpty(numSB.ToString()))
                {
                    numsList.Add(int.Parse(numSB.ToString()));
                    numSB = new StringBuilder();
                }
            }
        }

        if (!string.IsNullOrEmpty(numSB.ToString()))
        {
            numsList.Add(int.Parse(numSB.ToString()));
        }

    }

    private static List<int> GetNumbers()
    {
        List<int> numsList = new List<int>();

        string inputLine = "1";

        while (!string.IsNullOrEmpty(inputLine))
        {
            inputLine = Console.ReadLine().Trim();
            AddNumber(inputLine, ref numsList); //solve line: 34, 0FF, 5, $111, kk, !7, 10001011?
        }

        return numsList;
    } //when empty line is entered

    static void Main()
    {
        try
        {
            List<int> numsList = GetNumbers();

            long sum = numsList.Sum();

            double average = numsList.Average();

            Console.WriteLine("sum: {0}\r\naverage: {1}", sum, average);
        }
        catch (ArgumentNullException ane)
        {
            Console.WriteLine(ane.Message);
        }
        catch (OverflowException oe)
        {
            Console.WriteLine(oe.Message);
        }
        catch (InvalidOperationException ioe)
        {
            Console.WriteLine(ioe.Message);
        }
    }
}