 OOP: A rrrrapid review
 C / C++ and now … err … Java?
 Java: The new kid on the block!
 Regular Feature: Some Gyaaan !
 What NEXT?

 OOP is a relatively „new‟ programming paradigm
 Competes with Structured Programming
 Avoids REDUNDANCY, provides FLEXIBILITY
 Involves lot of jargons
 Modularity
 Abstraction / Data Encapsulation / Info Hiding
 Inheritance
 Polymorphism

 Procedural Programming: C
 C + Classes + … = C++
 Main problem: Lack of portability
 That‟s primarily what Java builds upon …

 Started by Sun Inc. under codename OAK
 The Retransformation
 HotJava
 Built on the WORA paradigm

 Stands for Write Once Read Anywhere
 Brainchild of James Gosling
 Stresses primarily on portability and strict
adherence to specifications
 Enters JVM!

 It‟s Java‟s own Interpreter
 Custom built for different platforms
 Just worry about your class file, Java
takes care of the rest!

Java Class File
Java Virtual Machine
Computing Architecture

 Header Files (Use import)
 Class Definition(s)
 main() within the class

Class <class name>
{
//datamembers
<access modifiers> <data type> <variable
name>
//function definitions
<access modifiers> <return type> <function
name> (comma-separated parameter list)
{
body – of – the - function
}
}

 Variables/Constants/Arrays
 Arithmetic Expressions/Operators
 Control Flow Techniques
 Pointers/References (???)
 Methods
 Classes/Objects
 …
 …
 <This is only a glimpse … > !!!

 An element that varies
 Vary = change
 Contrast with CONSTANTS (Rock
steady - do NOT change during
program run)
 8 types:
 byte, short, int, long,
 float, double,
 boolean,
 char

 Rules involving variables, constants,
operators etc.
 Always evaluate to a VALUE
 Can be used in a helluva innovative ways
 Master them and half the battle is one

 Sequence
 Embedded in the structure
 Selection
 If ... Else
 Switch
 Iteration
 For
 Do... While
 While

 A small program in itself
 Self contained
 Input-process-output
 Function prototype
 Function definition
 Arguments/Parameters

 Objects as references
 Call by Reference/Value
 Primitive datatypes – passed by value
 Objects – passed by reference
 Wrapper classes

 Case-sensitive
 Class Definitions do NOT end with a “;”
 No global variable concept
 No standalone main()
 No non-boolean value in conditional
statements

 No structs, enumerations, unions
 No scope unary scope resolution operator
 “.” operator
 super keyword
 Data-types sizes are FIXED, independent
of machine architecture

 Multiple inheritance NOT supported
 Exception handling typicality
 Treatment of ob1 = ob2 statements
 No destructors
 extends keyword

 Be Disciplined
 Be Regular
 Try and compete in online coding competitions
 Practice (Remember it makes a man perfect ...
and works for women as well!)
 Reference:
http://java.sun.com/docs/books/tutorial/getS
tarted/index.html