CustomFileProcessor

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
namespace PrzykladOdczytuZPliku
{
    public class CustomFileReader
    {
        private List<string> list1;

        private List<string> list2;

        public CustomFileReader()
        {
            list1 = new List<string>();
            list2 = new List<string>();
        }
        public void ReadDataFromFile(string path)
        {
            using (var reader = new StreamReader(path))
            {
                try
                {
                    while (reader.Peek() != 0)
                    {
                        ParseLine(reader.ReadLine());
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }

        private void ParseLine(string readLine)
        {
            string[] tmp_line = readLine.Split('-');
            list1.Add(tmp_line[0]);
            list2.Add(tmp_line[1]);
        }

        public void SaveDataToFile(string path)
        {
            using (var writer = new StreamWriter(path))
            {
                try
                {
                    for (int i = 0; i < list1.Count; i++)
                    {
                        var line = new StringBuilder();
                        line.Append(list1[i]);
                        line.Append('-');
                        line.Append(list2[i]);
                        writer.WriteLine(line);
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }
    }

    public class Program
    {
        static void Main(string[] args)
        {
            var fileProcesor = new CustomFileReader();
            fileProcesor.ReadDataFromFile("plik.txt");
            fileProcesor.SaveDataToFile("plik2.txt");
        }
    }
}