Unit I: Introduction to OOP and Java FundamentalsUnit I: Introduction to OOP and Java Fundamentals Object Oriented Programming - Abstraction – objects and classes - Encapsulation-

Unit I: Introduction to OOP and JavaFundamentals

Object Oriented Programming - Abstraction – objects andclasses - Encapsulation- Inheritance - Polymorphism- OOP inJava – Characteristics of Java – The Java Environment - JavaSource File -Structure – Compilation. FundamentalProgramming Structures in Java – Defining classes in Java –constructors, methods -access specifiers - static members -Comments, Data Types, Variables, Operators, Control Flow,Arrays , Packages - JavaDoc comments.

Data types, Variables, Operators

1P.Poovizhi/CS8392/Data types, Variables,Operators

7/25/2019

Variable Declaration

To declare a variable, you must specify the data type & give the variable a unique name.

7/25/2019P.Poovizhi/CS8392/Data types, Variables,Operators

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int a,b,c;

float pi;

double d;

char a;

Variable Initialization

To initialize a variable, you must assign it a valid value.


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pi =3.14f;

do =20.22d;

a=’v’;

combine variable declaration and initialization

Types of variables

Local Variables

Instance Variables

Static Variables


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Types of variables

1) Local Variables

Local Variables are a variable that are declared inside the body of amethod.

2) Instance Variables

Instance variables are defined without the STATIC keyword .Theyare defined Outside a method declaration. They are Object specificand are known as instance variables.

3) Static Variables

Static variables are initialized only once, at the start of the programexecution. These variables should be initialized first, before theinitialization of any instance variables.


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Example

class Guru99 {int data = 99; //instance variable static int a = 1; //static variable void method() {

int b = 90; //local variable }

}


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Data Types in Java

Primitive Data Types Non-primitive Data Types


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Primitive Data Types

Primitive Data Types are predefined and available within the Javalanguage. Primitive values do not share state with other primitivevalues.

There are 8 primitive types: byte, short, int, long, char, float, double,and boolean

Integer data types

byte (1 byte) short (2 bytes) int (4 bytes) long (8 bytes)


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Floating Data Type float (4 bytes) double (8 bytes)

Textual Data Type char (2 bytes)

Logicalboolean (1 byte) (true/false)


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Java Default Values

Data Type Default Value Default size

byte 0 1 byte

short 0 2 bytes

int 0 4 bytes

long 0L 8 bytes

float 0.0f 4 bytes

double 0.0d 8 bytes

boolean false 1 bit

char '\u0000' 2 bytes


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Data Types

Java is a strongly typed language. Every variable must have a declared type. There are eight primitive types in Java.

Four - integer types Two - floating-point number types One - character type char One - boolean type for truth values.


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Java Variable Type Conversion & Type Casting

A variable of one type can receive the value of anothertype.

Case 1: Variable of smaller capacity is be assigned to another

variable of bigger capacity.

This process is Automatic, and non-explicit is known as Conversion


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Java Variable Type Conversion & Type Casting

Case 2) Variable of larger capacity is be assigned toanother variable of smaller capacity.

In such cases, you have to explicitly specify the type castoperator. This process is known as Type Casting.


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Data Types


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Variables

Initializing the variableint vacationDays;System.out.println(vacationDays);

// ERROR--variable not initializedint vacationDays;vacationDays = 12;

Orint vacationDays = 12;


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Operators


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Operators

Arithmetic Operators


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Operators

Bitwise Operators


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Operators

Relational Operators


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Operators

Boolean Logical Operators


20

Assignment Operatorint x,y,z;x=y=z=100;

? Operatorexpression1 ? expression2 : expression3


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Type Conversion between Numeric


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Enumerated Types


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Reference

https://www.javatpoint.com/java-tutorial

http://nptel.ac.in/courses/106106147/

http://www.nptelvideos.com/java/java_video_lect

ures_tutorials.php

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P.Poovizhi/CS8392/Data types, Variables,Operators 7/25/2019

PPT Created by – Credits To

Sandra.K.S

Dhinesh Kumar S

Gokulkrishnan.R

Santhoshkumar A


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Sindhu.C

Sadhakrishnan.M

Abarna Jone J

Jithendran.R


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Documents

Unit I: Introduction to OOP and Java FundamentalsUnit I: Introduction to OOP and Java Fundamentals Object Oriented Programming - Abstraction – objects and classes - Encapsulation-