15

using System;
using System.IO;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TFYA_lab15
{
    class Program
    {
        static void Main(string[] args)
        {
            Regex regex = new Regex("часы",RegexOptions.IgnoreCase);
            string target = "таймер";
            string text = "";
            using (StreamReader sr = new StreamReader("D:\\Нужное\\ТФЯ\\lab15\\var5.txt",Encoding.UTF8))
            {
                text = sr.ReadToEnd();
                text = regex.Replace(text, target);
            }
            using (StreamWriter sw = new StreamWriter("D:\\Нужное\\ТФЯ\\lab15\\var5.txt", false, Encoding.UTF8))
            {
                sw.WriteLine(text);
            }
        }
    }
}