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using System;
using System.IO;

namespace _10_CopyFile
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length != 2)
            {
                Console.WriteLine("Usage: Copy srcFile destFile");
                return;
            }

            try
            {
                using (FileStream inputStream = new FileStream(args[0], FileMode.Open))
                using (FileStream outputStream = new FileStream(args[1], FileMode.Create))
                using (BinaryReader reader = new BinaryReader(inputStream))
                using (BinaryWriter writer = new BinaryWriter(outputStream))
                {
                    long length = inputStream.Length;

                    const int bufferSize = 1000000;
                    while (length > 0)
                    {
                        byte[] buffer = reader.ReadBytes(bufferSize);
                        writer.Write(buffer);
                        length -= buffer.Length;
                    }
                }
            }
            catch (IOException)
            {
                Console.Error.WriteLine("Usage: Copy srcFile destFile");
            }

        }
    }
}