You may be wondering what is device context. Here is the answer :-)
Structure that defines a set of graphic objects and their attributes is Device Context (DC)
In windows if you want to draw anything you have to first define a DC (think of it as paper) before you can draw anything. Usually these all are handled by VB, but if you are programming in VC you have to do it yourself. 
After defining the DC you have to select the object. It may be Bitmap, Brush, Pen, Font and Region

DC occupies system resources, so you must delete it once it has been used.

Author : Arsalan Aslam (Code Master)