Indexer (인덱서)
http://dis.dankook.ac.kr/lectures/hci09/entry/Indexer

Property (속성)
http://dis.dankook.ac.kr/lectures/hci09/entry/Property

Abstract Class (추상 클래스)
http://dis.dankook.ac.kr/lectures/hci09/entry/Abstract-class

Sealed Class (봉인 클래스)
http://dis.dankook.ac.kr/lectures/hci09/entry/Sealed-Class

polymorphism (다형성)
– Shape/Circle/Rectangle/Triangle/Square 클래스
– class 및 inheritance
– abstract class 및 polymorphism

ShapePolymorphism.zip