Introduction - If you have any usage issues, please Google them yourself
Write a drawing applet MiniDraw, required drawing a straight line (Line), Oval (Ellipse), rectangular (Rectangle), polygons (Polygon) and other graphic elements (primitives).
Xu Yong of each pixel of a class (object) to encapsulate, as CLine, CEllipse, CRect, CPolygon
A variety of primitives from a parent class CShape to succeed
Each pixel of the drawing is not the same, but draw the interface in the parent class is the same, so you can learn and use class polymorphism.