File

using java.util;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;

namespace SoftSvetlina
{
    class Program
    {
        static void Main()
        {
            List<int> nums = new List<int>();
            using (StreamReader reader = new StreamReader("numbers.txt"))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    nums.Add(int.Parse(line));
                }
            }

            nums.Sort();

            Console.WriteLine(string.Join(", ", nums));

            using (StreamWriter writer = new StreamWriter("numberssort.txt"))
            {
                foreach (var item in nums)
                {
                    writer.WriteLine(item);
                }
            }

        }
    }
}