text: ﻿using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  using System.Timers;
  using static System.Console;
  
  namespace Ch13Ex01
  {
      class Program
      {
          static int counter = 0;
  
          static string displayString =
                               "This string will appear one letter at a time. ";
          static void Main(string[] args)
          {
              Timer myTimer = new Timer(100);
              myTimer.Elapsed += new ElapsedEventHandler(WriteChar);
              myTimer.Start();
              System.Threading.Thread.Sleep(200);
              ReadKey();
          }
          static void WriteChar(object source, ElapsedEventArgs e)
          {
              Write(displayString[counter++ % displayString.Length]);
          }
      }
  }