how to read description for the code
<p>hi i send some c# code this is get from imagealg.dll file the class name is diff code is given below how to get description for this code.</p>

<pre><code>public sealed class Diff
{
// Fields
private int diff;
private Bitmap overlayImage;
private Bitmap overlayImage1;

// Methods
public Diff()
{
}

public Diff(Bitmap overlayImage, Bitmap overlayImage1)
{
    this.overlayImage = overlayImage;
    this.overlayImage1 = overlayImage1;
}

public int Apply(Bitmap srcImg, Bitmap dstImg)
{
    int width = srcImg.Width;
    int height = srcImg.Height;
    int num3 = dstImg.Width;
    int num4 = dstImg.Height;
    PixelFormat format = (srcImg.PixelFormat == PixelFormat.Format8bppIndexed) ? PixelFormat.Format8bppIndexed : PixelFormat.Format24bppRgb;
    BitmapData data = srcImg.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadOnly, format);
    BitmapData ovrData = dstImg.LockBits(new Rectangle(0, 0, num3, num4), ImageLockMode.ReadOnly, format);
    this.ProcessFilter(data, ovrData, format);
    dstImg.UnlockBits(ovrData);
    srcImg.UnlockBits(data);
    return this.diff;
}

public void ApplyInPlace(Bitmap img)
{
    int width = img.Width;
    int height = img.Height;
    if (((img.PixelFormat != this.overlayImage.PixelFormat) || (width != this.overlayImage.Width)) || (height != this.overlayImage.Height))
    {
        throw new ArgumentException();
    }
    if ((img.PixelFormat != PixelFormat.Format8bppIndexed) &amp;&amp; (img.PixelFormat != PixelFormat.Format24bppRgb))
    {
        throw new ArgumentException();
    }
    BitmapData bitmapdata = img.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
    img.UnlockBits(bitmapdata);
}

public int difference()
{
    return this.diff;
}

private unsafe void ProcessFilter(BitmapData data, BitmapData ovrData, PixelFormat fmt)
{
    int width = data.Width;
    int height = data.Height;
    int num3 = (fmt == PixelFormat.Format8bppIndexed) ? 1 : 3;
    int num4 = width * num3;
    int num5 = data.Stride - num4;
    byte* numPtr = (byte*) data.Scan0.ToPointer();
    byte* numPtr2 = (byte*) ovrData.Scan0.ToPointer();
    this.diff = 0;
    for (int i = 0; i &lt; height; i++)
    {
        int num8 = 0;
        while (num8 &lt; num4)
        {
            int num6 = numPtr[0] - numPtr2[0];
            string str = Convert.ToString(numPtr[0]);
            string str2 = Convert.ToString(numPtr2[0]);
            if (num6 != 0)
            {
                this.diff++;
            }
            num8++;
            numPtr++;
            numPtr2++;
        }
        numPtr += num5;
        numPtr2 += num5;
    }
}

// Properties
public Bitmap OverlayImage
{
    get
    {
        return this.overlayImage;
    }
    set
    {
        this.overlayImage = value;
    }
}
}
</code></pre>
