title: How to backup a complete file?
body: <p>What is the most efficient way to make a backup of a file when it's being opened into the program, so that when the user changes and saves it, there is always a way to go back?</p>
  
  <p>Example:</p>
  
  <pre><code>    private void open_click(object sender, EventArgs e)
      {
          ofd.DefaultExt = "";
          if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
          {
              fileIn = ofd.FileName;
              fileOut = Path.GetTempFileName();
              string encoded = File.ReadAllText(fileIn);
      etc. etc. etc
  }
  </code></pre>
  
  <p>The file that gets loaded into the program needs to get backed up as backup_01 and put in the same folder as the original file. When backup_01 exists, backup as backup_02, and so on).</p>
  
  <p>Examples are more than welcome!</p>