using System;
using System.Windows.Forms;
using System.IO;
class MainClass
{
public static void Main()
{
OpenFileDialog dlgOpen = new OpenFileDialog();
dlgOpen.Title="Select file to back up";
if (dlgOpen.ShowDialog() == DialogResult.OK)
{
FileStream inStream = File.OpenRead(dlgOpen.FileName);
FileStream outStream = File.OpenWrite(dlgOpen.FileName + ".bak");
int b;
while ((b = inStream.ReadByte()) > -1)
outStream.WriteByte( (byte) b);
outStream.Flush();
outStream.Close();
inStream.Close();
}
}
}