Java程序辅导
C C++ Java Python Processing编程在线培训 程序编写 软件开发 视频讲解
C C++ Java Python Processing编程在线培训 程序编写 软件开发 视频讲解
Inheritance Examples 1 Real-world Examples: Animals Source code: http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming Animal Dog Cat 2 3Example #2: Timepieces Multiple inheritance – A derived class can have more than one base class – Java does not support it – uses “interface” instead. 4 Example #3: Shapes Basic Shape Circle Polygon Ellipse Square HexagonRectangle 5 Example #4: Wireless Telephony Mobile initiated message Registration Call Processing SMS Origination Page Response 6 Value of inheritance? • Helps us to break software into manageable pieces • Existing classes can be morphed to design new classes – code reuse • Enables us to group different types of objects together and do some action on all of them. 7 Inheritance Examples in Java and C++ 8 Back to Example #1: Animals 9 Animal Dog Cat Want to group them together & make them talk? Concepts • Static binding vs. dynamic binding • Polymorphism using virtual methods • Abstract base class • Ability of base class pointers to point to derived class objects 10 Add Human? 11 Animal Dog Cat Human Want to group them together & make them talk? C++ 12 Animal Dog Cat Human AnimalActions Java: Interface 13 Animal Dog Cat Human AnimalActions Example from Wiki: Bad use of Inheritance 14 Parrot Human Whistler Example from Wiki 15 WhistlerParrot Human Concepts • Interface 16 C++ 17 Animal Dog Cat Human AnimalActions Java: Interface 18 Animal Dog Cat Human AnimalActions Inheritance Examples in Java and C++ 19 References • http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming - Animals : Inheritance coding examples in Java/C++/… • http://en.wikipedia.org/wiki/Interface_%28Java%29 – Java Interfaces 20