20120224170209MTS 3033- Bab1 Introduction to OOP

8/2/2019 20120224170209MTS 3033- Bab1 Introduction to OOP

1/41

Click to edit Master subtitle style

3/5/12MTS 3033 - OBJECT

Chapter 1

11

Introduction to objectoriented programming

MTS 3033 - OBJECT


2/41

3/5/12MTS 3033 - OBJECT ORIENTED

INTRODUCTION TO OOP

Objectives:

Know the concept of OOP

Know the difference between

functional programming and OOP Know basic terminology in OOP

Know the importance of OOP

Know four design principles of OOP

Know OOP programming languages

22MTS 3033 - OBJECT ORIENTED


3/41


INTRODUCTION TO OOP

Object oriented programming isintroduced as a new programmingconcept which should help one indeveloping high quality software.

It attempts to solve the problem withonly one approach by dividing theproblems in sub-modules and usingdifferent objects

Objects of the program interact bysending messages to each other.



4/41


INTRODUCTION TO OOP

Programming with objects is quite likeworking with real world objects.

It groups operations and data into

modular units called objects. These objects can be combined into

structured networks to form a completeprogram, similar to how the pieces in a

puzzle fit together to create a picture.



5/41


INTRODUCTION TO OOP

By breaking down complex softwareprojects into small, self-contained andmodular units, object orientation ensurethat changes to one part of softwareproject will not affect other portions ofthe software.



6/41


STRUCTURED vs. OOPROGRAMMING

STRUCTURED PROGRAMMING:

MAIN PROGRAM

FUNCTION 3FUNCTION 2

GLOBAL DATA

FUNCTION 5FUNCTION 4

FUNCTION1



7/413/5/12MTS 3033 - OBJECT ORIENTED

Structured Programming

There are features of structuredprogramming:

Emphasis is on doing things (algorithms)

Using function

Function & program is divided intomodules

Every module has its own data and

function which can be called by othermodules.

Most of the functions share global data




Structured Programming( Cont) Data move openly around the system

from function to function

Functions transform data from one form

to another Employs top down approach in program

design.




OBJECT ORIENTEDPROGRAMMING

Object1

Object 2

Data

Function

Data

Function

Object 3

Data

Function




OBJECT ORIENTEDPROGRAMMING

There are features of object orientedprogramming:

Emphasis is on data rather than

procedure Programs are divided into what are

known as objects

Data structures are designed such that

they characterize the objects. Functions that operate on the data of an

object are tied together in the datastructure




OBJECT ORIENTEDPROGRAMMING(2)

Data is hidden and cannot be accessedby external functions.

Objects may communicate with each

other through functions. New data and functions can be easily

added whenever necessary

Follows bottom-up approach in program

design.




THE DIFFERENCES BETWEENFUNCTIONAL PROGRAMMING

AND OOPFUNCTIONAL PROGRAMMING OOP

Emphasis is on doingthings (algorithms)

Emphasis is on datarather than procedure

Data and functions are keptseparately.

Data and functions are group inclass

Design is not very strong, hard tounderstand and difficult to

implement.

Design of the whole system couldbe understand by others (even

doesnt have background onscience computer)

Using top-down approach. Itbreaks a program down intocomponents until they cannot becomposed anymore.

Using bottom-upapproach in programdesign




Why chose oop?

Current problem of software:Software is difficult to develop, maintain andmodify.

Most software is over budget and delivered

late. Programmers still have to create software

from the ground-up.

OO introduces techniques that help:

Developing a more cost-effective and efficientsoftware that will be delivered on time.

Adapt quickly to new changes or clientdemand.




Pure OO Languages

Simula

Simulation programming language

Found in the late 1960sBy O.J. Dahl and Kristen Nygaard

SmalltalkIntroduced in the early 1970sBy Alan KayFirst successful object oriented

language.

Object-OrientedProgramming

Languages


Obj t O i t d



Object-OrientedProgramming

LanguagesHybrid OO LanguagesC++, Eiffel, etc

Emerged in the mid 1980s




OOP offers several advantages to both programdesigner and the user. Object orientationcontributes to the solution of many problemsassociated with the development and quality

software and lesser maintenance cost. Theprinciples advantages are :

i. Through inheritance, we can eliminateredundant code and extend the use ofexisting class

ii. We can build programs from the standardworking modules that communicate widthone another, rather than having to startwriting the code from scratch. This leads

to saving development time and higher

Advantages using oop




iii.The principle of data hiding helpsthe programmer to build secureprograms that cannot be invadedby code in other parts of program.

iii. It is easy to partition the work in aproject based on objects.

iii. Object oriented system can be

easily upgraded from small to largesystems.

Advantages using oop




BASIC TERMINOLOGY OFOBJECT ORIENTED

PROGRAMMINGi. Objectii. Class

iii. MessageObject Communication

i. Encapsulation

ii. Abstraction

iii. Inheritanceiv. Polymophism


BASIC TERMINOLOGY OF




PROGRAMMING(Cont)The key concepts are:Object

-Directly relate to the real world

entities.-Can be a person, thing or concept(a noun).

-Like a black box, therefore all theimplementation is hidden.






PROGRAMMING(Cont)Object has aAttribute - description ofobjects in a classMethod - an action performedby an object (a verb)Identity (unique name)






PROGRAMMING(Cont)Example for attributes and methodsAttributes:

manufacturers name

model nameyear madecolor

number of doorssize of engineetc.






PROGRAMMING(Cont)Methods:Define data items (specifymanufacturers name, model,

year, etc.)Change a data item (color,engine, etc.)Display data itemsCalculate costetc.






PROGRAMMING (Cont) Class A generic definition for a set of

similar objects.

Provides the specifications forthe objects behaviors andattributes.

An abstraction of a real worldentity.






PROGRAMMING(Cont)Object vs Classobject is created from a class.object is considered as an instance of a

class.class is considered as a template from

which objects are instantiatedcan create an object or many objects from

a class.






PROGRAMMING(Cont)

Diagram 1: ClassCar Car

DoorSeatTypeModel

DriveStopLockUnlock

Diagram 2: MyCaras an Object

Object vs Class


BASIC CONCEPT OF



BASIC CONCEPT OFOBJECT ORIENTED

PROGRAMMING(Cont) Messages

Requests for the receiverobjects to carry out the

indicated method or behaviorand return the result of thataction to the sender objects




27/41



PROGRAMMING(Cont)Object Communications

Objects communicate by sending

messages



28/41

3/5/12MTS 3033 - OBJECT ORIENTED 28MTS 3033 - OBJECT ORIENTED


29/41

3/5/12MTS 3033 - OBJECT ORIENTED 29MTS 3033 - OBJECT ORIENTED


30/41


Design Principles of OOP

Four main design principles of Object-Oriented Programming(OOP):

Abstraction

Encapsulation

Polymorphism Inheritance



31/41


Abstraction

Data abstraction is a process todelete all unnecessary attributes andremain the necessary attributes todescribe an object.

Object in a program is an abstractionfrom a real object (in real world).

Attributes characteristics, which can

be seen. Behaviours actions that are done

to an object.

Figure 1.1 shows how data

abstraction is done for class Student31MTS 3033 - OBJECT ORIENTED


32/41


Abstraction

CHARACTERISTIC/ATRRIBUTES

BEHAVIOUR/METHOD

ABSTRACTION

OBJECTSTUDENT

NAME, MATRIK

NUMBER, ADDRESS, ICNUMBER

CALCULATE_MARK (),DETERMINE_GRED(),PRINT_RESULT()

FIGURE 1.1

CLASSSTUDENT



33/41


Abstraction

OBJECT

BOX

ABSTRACTION

CHARACTERISTIC/ATRRIBUTES

BEHAVIOUR/METHOD

OBJECT BOX

Length, width, depth

Calculate_Volume()Calculate_Area()

CLASS BOX

FIGURE 1.2



34/41


Abstraction

Focus only on the important factsabout the problem at hand

To design, produce and describe sothat it can be easily used without

knowing the details of how it works.Analogy: When you drive a car, you dont

have to know how the gasoline and

air are mixed and ignited. Instead you only have to know how

to use the controls.Draw map



35/41


Encapsulation

Encapsulation is a process of tyingtogether all data and methods thatform a class and control the access todata by hiding its information.

It enables access to object just byusing methods of that object.

It is one of the security features inobject-oriented programming (OOP).

Figure 1.3 shows the concept ofencapsulation for a class Student andFigure 1.4 for class Box.



36/41


Encapsulation

Student

private :int matricNumint icNum

char name[30]char address[100]

public :doublecalculate_mark()voiddetermine_mark()void print_result()

Box

private :float lengthfloat width

float depth

public :floatcalculate_volume()float area()

FIGURE 1.3 FIGURE 1.4



37/41


Encapsulation

Also known as data hiding Only objects methods can modify

information in the object.

Process of hiding the implementationdetails of an object.

Access to manipulate the object datais through its interface (operations/

functions). Protects an objects internal state

from being corrupted by otherprograms.



38/41


Encapsulation

Program maintenance is easier andless expensive because changes inthe object data or implementation isonly modified in one place

Allows objects to be viewed as blackboxes.



39/41


Polymorphism

the same word or phrase can meandifferent things in different contexts

Analogy:

In English, bankcan mean side of a

river or a place to put moneymove -



40/41


Inheritance

Inheritancea way of organizingclasses

Term comes from inheritance oftraits like eye color, hair color, and so

on. Classes with properties in common

can be grouped so that their commonproperties are only defined once.

Superclass inherit its attributes &methods to the subclass(es).

Subclass can inherit all its

superclass attributes & methods40MTS 3033 - OBJECT ORIENTED


41/41

Click to edit Master subtitle style

An Inheritance Hierarchy

Vehicle

Automobile Motorcycle Bus

Sedan Sports Car School BusLuxury Bus

What properties does each vehicleinherit from the types of vehiclesabove it in the diagram?

Superclass

Subclasses

20120224170209MTS 3033- Bab1 Introduction to OOP

Documents

Transcript of 20120224170209MTS 3033- Bab1 Introduction to OOP