Note for Object Oriented Modeling and Design - OOMD By Bhavya Balakrishnan

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AMC Engineering College AMC ENGINEERING COLLEGE DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING Objects can be concrete (such as a file in a file system) or conceptual (such as scheduling policy in a multiprocessing OS). Each object has its own inherent identity.(i.etwoobjectsaredistinctevenifalltheirattributevaluesareidentical). 1 Classification:  Classification means that objects with the same data structure (attribute) and behavior(operations)aregroupedintoaclass.  E.g. paragraph, monitor, chesspiece.  Each object is said to be an instance ofits class.  Fig below shows objects and classes: Each class describes a possibly infinite set of individualobjects. Inheritance: Dept. of CSE 10CS71 Bhavya

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AMC Engineering College  It is the sharing of attributes and operations (features) among classes based on a hierarchical relationship. A super class has general information that sub classes refine andelaborate.  E.g. Scrolling window and fixed window are sub classes ofwindow. 1 Polymorphism:  Polymorphism means that the same operation may behave differently for differentclasses.  For E.g. move operation behaves differently for a pawn than for the queen in a chessgame. Dept. of CSE 10CS71 Bhavya

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AMC Engineering College Note: An operation is a procedure/transformation that an object performs or is subjected to. An implementation of an operation by a specific class is called a method. WHAT IS OO DEVELOPMENT? 1 Development refers to the software life cycle: Analysis, Design and Implementation. The essence of OO Development is the identification and organization of application concepts, rather than their final representation in a programming language. It’s a conceptual process independent of programming languages. OO development is fundamentally a way of thinking and not a programmingtechnique. OO methodology 1 wH eeprreesenta processfor OOdevelopment and a graphical notation for representing OO concepts.The process consists of building a model of anapplicationandthenaddingdetailstoitduringdesign. 1 The methodology has the following stages  System conception: Software development begins with business analysis or usersconceivinganapplicationandformulatingtentativerequirements. Dept. of CSE 10CS71 Bhavya

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AMC Engineering College  Analysis: The analyst scrutinizes and rigorously restates the requirements from the system conception by constructing models. The analysis model is a concise, preciseabstractionofwhatthedesiredsystemmustdo,nothowitwillbedone.  The analysis model has twoparts- Dept. of CSE 10CS71 Bhavya