C#

FileStream tmpStream = new FileStream(filename, FileMode.Create);
tmpStream.Close();

private void WipeFile(string filename, int timesToWrite)
{
    if(File.Exists(filename))
    {
        byte[] dummyBuffer = new byte[512];
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        rng.GetBytes(dummyBuffer);

        double filelength = new FileInfo(filename).Length;
        double sectors = System.Math.Ceiling(filelength / 512);

        for (int timesWritten = 0; timesWritten < timesToWrite; timesWritten++)
        {
            FileStream inputStream = new FileStream(filename, FileMode.Open, FileAccess.Write, FileShare.None);                                         

            int sectorsWritten = 0;
            while (sectorsWritten < sectors)
            {
                inputStream.Write(dummyBuffer, 0, dummyBuffer.Length);
                rng.GetBytes(dummyBuffer);
                sectorsWritten++;
            }

            inputStream.Close();
        }

        FileStream tmpStream = new FileStream(filename, FileMode.Create);
        tmpStream.Close();

        File.Delete(filename);
    }
}

FileStream tmpStream = new FileStream(filename, FileMode.Truncate);
tmpStream.Close();

FileStream tmpStream = new FileStream(filename, FileMode.Create);
tmpStream.Close();

private void WipeFile(string filename, int timesToWrite)
{
    if(File.Exists(filename))
    {
        File.SetAttributes(filename, FileAttributes.Normal);

        double sectors = System.Math.Ceiling(new FileInfo(filename).Length / 512.0);
        byte[] dummyBuffer = new byte[512];

        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        rng.GetBytes(dummyBuffer);

        FileStream inputStream = new FileStream(filename, FileMode.Open);
        for (int timesWritten = 0; timesWritten < timesToWrite; timesWritten++)
        {
            inputStream.Position = 0;
            int sectorsWritten = 0;
            while (sectorsWritten < sectors)
            {
                inputStream.Write(dummyBuffer, 0, dummyBuffer.Length);
                rng.GetBytes(dummyBuffer);
                sectorsWritten++;
            }
        }
        inputStream.SetLength(0);
        inputStream.Close();

        DateTime dt = new DateTime(2037, 1, 1, 0, 0, 0);
        File.SetCreationTime(filename, dt);
        File.SetLastAccessTime(filename, dt);
        File.SetLastWriteTime(filename, dt);

        File.Delete(filename);
    }
}

<br />
inputStream.Write(dummyBuffer, 0, dummyBuffer.Length);<br />
rng.GetBytes(dummyBuffer);<br />

static class Program
  {
  /// <summary>
  /// The main entry point for the application.
  /// </summary>
  [STAThread]
  static void Main(string[] args)
    {
    foreach (string arg in args)
      {
      // do something with arg ...
      }
    }
  }

humdumof wrote:

a) which one is good practice to carry out ?

humdumof wrote:

b) what the difference between them ?

humdumof wrote:

c) Even though we have VS, somtime we design/use control thru coding, why ?