C# Program to Compare Two Text Files

/*
 * C# Program to Perform File Comparison
 */
using System;
using System.Threading;
using System.IO;
 
class Reader
{
    string fileName;
    public string data;
 
    public Reader(string fn) { fileName = fn; }
 
    public void Read()
    {
        FileStream s = new FileStream(fileName, FileMode.Open);
        StreamReader r = new StreamReader(s);
        data = r.ReadToEnd();
        r.Close();
        s.Close();
 
    }
}
class ThreadSample
{
    static void Main(string[] arg)
    {
        if (arg.Length == 2)
        {
            Reader a = new Reader(arg[0]);
            Reader b = new Reader(arg[1]);
            Thread ta = new Thread(new ThreadStart(a.Read));
            Thread tb = new Thread(new ThreadStart(b.Read));
            ta.Start();
            tb.Start();
            ta.Join();
            tb.Join();
 
            if (a.data.Length == b.data.Length)
            {
                int i = 0;
                while (i < a.data.Length && a.data[i] == b.data[i]) i++;
                if (i == a.data.Length)
                Console.WriteLine("Files {0} and {1} are equal", arg[0], arg[1]);
                else
                Console.WriteLine("Files {0} and {1} are not equal", arg[0], arg[1]);
            }
            else
            {
                Console.WriteLine("Files {0} and {1} are not equal", arg[0], arg[1]);
            }
        }
        else
        {
            Console.WriteLine("-- enter two file names");
        }
        Console.ReadLine();
    }
}