Week 1 Sessions 1-2 Slides 1-15 Introduction to OOP

7/31/2019 Week 1 Sessions 1-2 Slides 1-15 Introduction to OOP

1/15

PROGRAMMING PARADIGM

Style of Programming in which the programming task isbroken down into a series of operations (calledprocedures) applied to data (or data structures)

C and Pascal

2. Object-Oriented Programming

Extension of procedural programming

Breaks down a programing task into a series ofinteractions among different entities or objects

Java, C++, and Smalltalk

1. Procedural Programming


2/15

OBJECT ORIENTED PROGRAMMING

Type of programming in which programmers definenot only the data stuctures, but also the types ofoperations (methods) that can be applied to the datastuctures.

Enables programmers to create modules that do notneed to be changed when a new type of object isadded.

Most widely used paradigm

Instead of focusing on what the system has to do,focus on:

what objects the system containshow they interact towards solving the

programming problem


3/15

ILLUSTRATION OF OOP


4/15


Advantages of OOP over Conventional Approaches:it provides a clear modular structure for programs

which makes it good for defining abstract data typeswhere implementation details are hidden and the unithas a clearly defined interface.

it makes it easy to maintain and modify existing codeas new objects can be created with small differencesfrom existing ones.

it provides a good framework for code librarieswhere supplied software components can be easilyadapted and modified by the programmer. This isparticularly useful for developing graphical userinterfaces.


5/15


Key OOP Concepts:Objects

Classes

Inheritance

Encapsulation

Polymorphism

Abstraction


6/15

OBJECT AND CLASSES Objects

Represent things from the real world

Made up ofAttributes characteristics that define an objectMethods self-contained block of program code

similar to procedureExample:

A cars attributes are make, model, year, & purchase priceA cars methods are forward and backward

Define a type of object

ClassesTerm that describes a group or collection of objects

with common properties

Specifies methods and data that type of objects has

Example:

EmployeeCar


7/15

ABSTRACTION

Allows a programmer to hide all but the relevant

information (to the problem at hand) about an objectin order to reduce complexity and increase efficiency

Closely related to encapsulation and informationhiding


8/15

ENCAPSULATION

refers to the hiding of data (attributes) and

methods within an object

protects an objects data from corruption

protects the objects data from arbitrary and

unintended use hides the details of an objects internal

implementation from the users of an object

separates how an object behaves from how it is

implemented.

easier to modify programs since one object type ismodified at a time.


9/15

ILLUSTRATION OF ENCAPSULATION


10/15

INHERITANCE

the process by which objects can acquire (inherit)

the properties of an ojects of other class

Provides reusability, like adding additional features

to an existing class without modfying it.


11/15

INHERITANCE


12/15

POLYMORPHISM

refers to the ability to process objects differently

depending on their data type or class

the ability to redefine methods for derived classes

request for an operation can be made withoutknowing which specific method should be invoked


13/15

POLYMORPHISM


14/15

ABSTRACT CLASSES

Class that is not used to creare (instantiate) objects

designed to act as a base class (to be inherited by

other classes)

design concept in program development andprovides a base upon which other classes are built.

can only specify members that shoukd beimplemented by all inheriting classes


15/15

INTERFACES

Allow you to create definitions for component

interaction

provide another way of implementing

polymorphism

specify methods that a component must implementwithout actually specifying how the method isimplemented

Week 1 Sessions 1-2 Slides 1-15 Introduction to OOP

Documents