Remove HTML tags from .csv files

using System;
using System.Diagnostics;
using System.IO;
using System.Text;

namespace HTMLTagRemove
{
    internal class Program
    {
        private const string INPUT_FILENAME = "termekek.csv";
        private const string OUTPUT_FILENAME = "termekek_result.csv";

        private static void Main()
        {
            string[] rows;
            using (var reader = new StreamReader(INPUT_FILENAME, Encoding.Default))
            {
                rows = reader.ReadToEnd().Split(new[] { '\t' }, StringSplitOptions.RemoveEmptyEntries);
            }
            rows = RemoveHtmlTags(rows);
            using (var writer = new StreamWriter(OUTPUT_FILENAME, false, Encoding.UTF8))
            {
                writer.Write(string.Join(";", rows));
            }
            Process.Start(OUTPUT_FILENAME);
        }

        private static string[] RemoveHtmlTags(string[] strings)
        {
            for (int i = 0; i < strings.Length; i++)
            {
                strings[i] = RemoveTagInString(strings[i]);
            }
            return strings;
        }

        public static string RemoveTagInString(string sourceString)
        {
            var charray = new char[sourceString.Length];
            int index = 0;
            bool isInside = false;
            foreach (char character in sourceString)
            {
                if (character == '<')
                {
                    isInside = true;
                    continue;
                }
                if (character == '>')
                {
                    isInside = false;
                    continue;
                }
                if (isInside) continue;

                charray[index] = character;
                index++;
            }
            return new string(charray, 0, index);
        }
    }
}