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BITS Pilani, Pilani Campus

BITS PilaniPilani Campus

Dr. Yashvardhan SharmaCSIS Dept., BITS-Pilani

IS F213 Object Oriented Programming


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Contact Info

• Email: [email protected]• Course Web site: http://csis/faculty/yash/OOP/ISF213.htm

Apr 10, 2023

mailto:[email protected]

http://csis/faculty/yash/OOP/ISF213.htm

http://csis/faculty/yash/OOP/ISF213.htm


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Course Information

• Three Lectures / Week– M W F – 12:00 -12:50 PM

• Labs: 3 hours/week– T TH – 2:00- 5:00 PM

• Total Lectures: 40(Planned)• Text Books:

– T1: Object Oriented Design & Patterns, Cay Horstmann, John Wiley & Sons, 2nd Edition, 2006

• Reference Books :– 1. The complete Reference Java 2, 5th Edition, Herbert Schildt, Tata

McGraw Hill publishing– 2. JavaTM Design Patterns – A Tutorial, James W. Cooper, Addison-Wesley,

2000Apr 10, 2023


Today’s Agenda

• Course Overview• Object Basics• Three Pillars of OOP• Basic Java Syntax • Compiling/Executing Java Programs


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Evaluation Scheme:

Component Duration Date, Time and Venue

Marks Nature

Midsem Test 50 minutes 50 Closed Book

Tutorials 30 minutes 30 Closed Book

Online Test 90 minutes 40 open book

Comprehensive 3 hours 80 Partly open book


What’s Object• Term Object Means Combination of Data (Attributes) and Logic (Behavior,

Functions, Operations) of some real world entity• Every object has two parts :

- Data Part [ Instance Fields in Java, Attributes or properties]- Operations Part [ methods in java, Behavior]

• Examples :1. Account :

Attributes : Account Holder, Account type [saving , current] , Balance Opeartions : deposit, withdraw,

2. BOX: Attributes : length, width, height, color Operations : compute area, compute volume

Data

Methods Methods

Methods Methods

Object keeps Data Part + Operation Part Together


What’s class

• Objects are grouped in classes• Class collections of objects having similar

behavior and properties• A single object is simply an instance of class.• Objects can not be instantiated (or created)

without defining a class• Classes are defined whereas objects are

created.


Object State• Properties/Attribute Values at a particular moment represents the state of an

object• Object may or may not change state in response to an outside stimuli. • Objects whose state can not be altered after creation are known as immutable

objects and class as immutable class [ String class in Java]• Objects whose state can be altered after creation are known as mutable objects

and class as mutable class [ StringBuffer class in Java]

States of Three Different INSTANCES of CAR CLASS

MARUTI800

Name : maruti800Price : 200789Color : Red

MarutiESTEEM

Name : marutiEsteemPrice : 500789Color : whilte

MARUTIZEN

Name : marutiZenPrice : 200789Color : metallic white


Data Abstraction

• Way of managing complexity• Abstraction refers to the act of representing

essential features that are of interest of the users without including background details or explanation

• Classes use the concept of encapsulation for hiding unnecessary implementation details


Pillars of OOP

• Encapsulation• Inheritance• Polymorphism


Encapsulation

• Encapsulation means wrapping up of data and methods (operations , code) together

• Access to code and data is tightly controlled. • Through we can define what and what can not be

accessible outside. [ public , private , protected ]

Data

Methods Methods

Methods Methods

Encapsulation keeps Data Part + Operation Part Together inside a capsule


Encapsulation Example

class BOX

{

private double length;

private double width;

private double height;

public double area() { }

public double volume() { }

} // End of class BOX

lengthwidthheight

area()

volume()

BOX Class


Inheritance

• Process by which one object acquires properties of other classes• Supports Reusability of code and data• The class whose properties are extended is known as super or base or

parent class.• The class which extends the properties of super class is known as sub

or derived or child class • In Java a class can either extends another class or can implement an

interface

A

B <<class>>

<<interface>>A

B

<<class>>

<<class>>

class B extends A class B implements A


Various Forms of Inheritance

A

B

Single Inheritance

A

B

Hierarchical Inheritance

X

A B C

X

A B C

MultiLevel Inheritance

A

B

C

A

B

C

A B

C

Multiple InheritanceNOT SUPPORTED BY JAVA

A B

C

SUPPORTED BY JAVA


Polymorphism

• Poly means many and morph means forms. • One Interface Many forms• One Interface for several general class of actions• In Java we have two types of polymorphisms 1. Compile-Time [ Method Overloading]2. Run-Time [ Method Overriding]


Method OverLoading

• Two methods are said to be overloaded if they have same name and different signatures.

• Signature of method means number of arguments to method and their types.

• Two methods are said to have different signatures if they differ in number of arguments they receive or their types

• Example Signature

1. int sum (int a, int b)

2. float sum (int a, float b)

3. double sum(double a , double b)

4. void draw();

sum(int,int)

sum(int,float)

sum(double,double)

draw()

Note : return type and name of arguments are not part of signatures

Signatures


Method Overloading Examples

1. void sum(int a,int b)

2. int sum(float a, float b)

3. double sum (double a , double b)

4. int sum(int a, float b)

5. float sum(float a,int b)

Overloaded Methods

1. void sum(int a,int b)

2. int sum(int x, int y)

3. double sum (double a , double b)

4. float sum(double a1, double b)

1,2 and 3,4 Not Overloaded

1,3 and 2,4 are overloaded


Java Features

• Compiled and Interpreted• Platform Independent• Architectural Neutral


Java Program Structure

Documentation Section1. /**…… */ Documentation Comments2. // Single Line Comment3. /*…… */ Multi line Comments

Package Statement

Import Statements

Interface Statements

Class Definitions

Main Method class


Compiling/Executing a Java Application

Source Code

Java Compiler

ByteCode

<< .java file>>

<< javac .java >>

<< .class file>>

Java Interpreter

Machine Code

<< java [name of class] >>

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