Object oriented programming concept

Object oriented programming concept

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  Object Oriented Programming Concept Prepared By: Pina Chhatrala
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  Introduction  It isa type of programming in which programmers define not only the data type of a data structure, but also the types of operations (functions) that can be applied to the data structure.  In this way, the data structure becomes an object that includes both data and functions.  In addition, programmers can create relationships between one object and another. For example, objects can inherit characteristics from other objects.  One of the principal advantages of object-oriented programming techniques over procedural programming techniques is that they enable programmers to create modules that do not need to be changed when a new type of object is added.  A programmer can simply create a new object that inherits many of its features from existing objects.  This makes object-oriented programs easier to modify. 2
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  Object  Objects arethe basic run-time entities in an object-oriented system.  When a program is executed, objects interact with each other by sending messages.  Different objects can also interact with each other without knowing the details of their data or code.  An object is an instance of a class.  A class must be instantiated into an object before it can be used in the software.  More than one instance of the same class can be in existence at any one time. 3
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  Class  A classis a collection of objects of a similar type.  Once a class is defined, any number of objects can be created which belong to that class.  A class is a blueprint, or prototype, that defines the variables and the methods common to all objects of a certain kind. 4
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  Instance  The instanceis the actual object created at runtime.  One can have an instance of a class or a particular object. 5
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  State  The setof values of the attributes of a particular object is called its state.  The object consists of state and the behaviour that's defined in the object's class. 6
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  Method  Method describesthe object’s ability.  A Bird has ability to Fly. So Fly() is one of the method of the Bird class. 7
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  Message Passing  Theprocess by which an object sends data to another object or asks the other object to invoke a method.  Message passing corresponds to "method calling". 8
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  Abstraction  Abstraction refersto the act of representing essential features without including the background details or explanations.  Classes use the concept of abstraction and are defined as a list of abstract attributes. 9
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  Encapsulation  It isthe mechanism that binds together code and data in manipulates, and keeps both safe from outside interference and misuse.  In short, it isolates a particular code and data from all other codes and data.  A well-defined interface controls the access to that particular code and data.  The act of placing data and the operations that perform on that data in the same class.  The class then becomes the 'capsule' or container for the data and operations.  Storing data and functions in a single unit (class) is encapsulation.  Data cannot be accessible to the outside world and only those functions which are stored in the class can access it. 10
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  Inheritance  It isthe process by which one object acquires the properties of another object.  This supports the hierarchical classification.  Without the use of hierarchies, each object would need to define all its characteristics explicitly.  However, by use of inheritance, an object need only define those qualities that make it unique within its class.  It can inherit its general attributes from its parent.  A new sub-class inherits all of the attributes of all of its ancestors. 11
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  Polymorphism  Polymorphism meansthe ability to take more than one form.  An operation may exhibit different behaviours in different instances.  The behaviour depends on the data types used in the operation.  It is a feature that allows one interface to be used for a general class of actions.  The specific action is determined by the exact nature of the situation. In general, polymorphism means "one interface, multiple methods", This means that it is possible to design a generic interface to a group of related activities.  This helps reduce complexity by allowing the same interface to be used to specify a general class of action.  It is the compiler's job to select the specific action (that is, method) as it applies to each situation. 12
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  Generalization  Generalization describesan is-a relationship which represent a hierarchy between classes of objects.  Eg:- a “Bird" is a generalization of “Dove", “Sparrow", “Parrot" and many others. 13
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  Specialization  Specialization meansan object can inherit the common state and behavior of a generic object.  However, each object needs to define its own special and particular state and behavior.  Specialization means to subclass. Bird is the generalization and Sparrow is the specialization, indicating that a Sparrow is a special kind of Bird. 14
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  Advantage of OOP OOP provides a clear modular structure for programs which makes it good for defining abstract data types where implementation details are hidden and the unit has a clearly defined interface.  OOP makes it easy to maintain and modify existing code as new objects can be created with small differences to existing ones.  OOP provides a good framework for code libraries where supplied software components can be easily adapted and modified by the programmer. 15
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  Special Thanks http://www.codeproject.com/Articles/27775/Object-Oriented-Programming- Concepts 16
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  Thank  You 17