oops unit 1

8/9/2019 OOPs Unit 1

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Object Orientation

Fundamentals & Overview toProgramming language C++

Bhagwant Singh


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Index

Procedure Oriented Programming

OOP Paradigm

Basic concept of object oriented program

Benefits of OOPs

Evolution of C++.

Input and Output operator.

Structure of C++ program

Tokens

ata t!pes


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Procedure-OrientedProgramming

"ie#ed as t$e se%uence of t$ings to be done

T$e primar! focus is on functions

&ierarc$ical decomposition

In a multi'function program( man!

important data items are placed as global

but in a large program it is ver! difficult to

identif! #$at data is used b! #$ic$

function.

)unctions are action'oriented and do not

reall! corresponding to t$e element of t$e

problem.


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OOPS Paradigm

Object Oriented Programming *OOP is an approac$ to program organi,ation anddevelopment t$at attempts to eliminate some of t$e pitfalls of conventional programming

met$ods b! incorporating t$e best of structured programming features #it$ several

po#erful ne# concepts.

Ties data more closel! to t$e function t$at operate on it.

OOP allo#s decomposition of a problem into a number of entities called objects and t$en

builds data and function around t$ese objects.


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Features

Emp$asis is on data rat$er t$an procedure.

Programs are divided into #$at are kno#n as objects.

ata structures are designed suc$ t$at t$e! c$aracteri,e t$e objects.

)unctions t$at operate on t$e data of an object are ties toget$er in t$e data structure.

ata is $idden and cannot be accessed b! e-ternal function.

Objects ma! communicate #it$ eac$ ot$er t$roug$ function.

e# data and functions can be easil! added #$enever necessar!.

)ollo#s bottom up approac$ in program design.


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Basic Concepts of OOPs

Objects

Classes

Data abstraction and encapsulation Inheritance

Polymorphism

Dynamic binding

Message passing


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Benets T$roug$ in$eritance( #e can eliminate redundant code e-tend t$e use of e-isting

Classes.

/e can build programs from t$e standard #orking modules t$at communicate

#it$ one anot$er( rat$er t$an $aving to start #riting t$e code from scratc$. T$is

leads to saving of development time and $ig$er productivit!.

T$e principle of data $iding $elps t$e programmer to build secure program t$at

can not be invaded b! code in ot$er parts of a programs. It is possible to $ave multiple instances of an object to co'e-ist #it$out an!

interference.

It is possible to map object in t$e problem domain to t$ose in t$e program.

It is eas! to partition t$e #ork in a project based on objects.

T$e data'centered design approac$ enables us to capture more detail of a modelcan implemental form.

Object'oriented s!stem can be easil! upgraded from small to large s!stem.

0essage passing tec$ni%ues for communication bet#een objects makes to

interface descriptions #it$ e-ternal s!stems muc$ simpler.

Soft#are comple-it! can be easil! managed.


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!"olution O# C$$

C$$ was de"eloped by BjarneStroustrup at %&'& Bell (aboratoriesin Murray )ill* +ew ,ersey* -S%* in the

early ./012s3 C$$ is an extension o# C

4arious #eatures o# C$$ enable

creating o# abstract data types* inheritproperties #rom existing data typesand support polymorphism3


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C$$ Program

5include6iostream7-sing namespace std8

intmain9:

;

cout66< =elcome to C$$>n


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+amespace is a new concept introducedby the %+SI C$$ standards committee3

&his denes a scope #or the identiersthat are used in a program3

In C$$* main 9: returns an integer "alue

to the operating system3 &here#ore* e"erymain 9: in C$$ should end with a return91: statement8 otherwise a warning anerror might occur3 Since main 9: returns

an integer type #or main 9: is explicitlyspecied as int. +ote that the de#aultreturn type #or all #unction in C$$ is int3


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Input %nd Output Operator

Input Operator @

Cin77 siAe8

Cin is Standard input stream

It causes the program to wait #or the user to type in a

number

&he operator 77 is nown as extraction or get#romoperator3

Output Operator @

Cout 66 &he SiAe is 66 siAe8Cout is Standard output stream

&he operator 66 is called the insertion orput tooperator3


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5include6iostream3h7

-sing namespace std

"oid main9:;

int a.1118

cout 66 a is 66a66endl8cout 66enter number


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Classes and Objects

% Class is a static description o# a type

It encapsulates the data and all legal

operations on that data

It also denes who has access to that data

%n object is an instance o# a class9sometimes we say an instantiation:


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5include6iostream3h7

using namespace std8

class person

;

char nameG1H8

Int age8

public@"oid getdata9"oid:8

"oid display9"oid:8

?8

"oid person @@ getdata9"oid:

;

cout 66 !nter name@ 8

cin 77 name8

cout 66 !nter age@ 8

cin 77 age8

?

4oid person @ @ display9"oid:

;

cout 66 >n+ameame@ 66 name8

cout 66 >n%ge@ 66 age8

?

Intmain9:

;person p8

p3getdata9:8

p3display9:8

eturn 18

?


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Client Ser"er Model


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&oens

Smallest indi"idual units in a programe is called astoens3

Jeywords are explicitly reser"ed identier that can2tbe used as names #or the programe "ariable3

Identiers re#er to the names o# "ariables* #unctions*arrays * classes etc

Major diKerence between the C and C$$ is the limiton the length o# a name3 C recogniAe only rst GL

characters o# the name but there no such limit in C$$

=chart type is a wideNcharacter literal introduce byC$$


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Data types

C$$ Datatypes

-serDenedStructure

-nionClass

!numeration

Deri"edtype

%rrayFunctionPointer

e#erence

Build in &ype

Integral &ype Floating &ype4oid

Int Char oatDoubl

e


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4oid

-ses o# 4oid&o speci#y the return type o# a #unction when

it is not returning any "alue3

&o indicate empty argument list to a #unction&o declare a generic Pointers3

4oid gp8

Statement .

Int ip8gp ip8

Statement G

ip gp8


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Structure "Qs -nion

% structure is dened withRstruct2 eyword3

%ll members o# the structurecan be manipulatedsimultaneously3

&he siAe o# structure objectis eEual to the sum o# theindi"idual siAe o# themember #unction3

Structure member areallocated distinct memorylocation3

Structure are not consideredas memory ecient3

%n -nion is dened withRunion2 eyword3

Members o# the union canbe manipulated only one

at a time3 &he siAe o# union object is

eEual to the siAe o# thelargest member #unction3

-nion member share

common memory space#or their exclusi"e usage3

-nion are not consideredas memory ecient3


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!numeration

%n enum is a user dened data type whichpro"ides away #or attaching name to anumbers* thereby increasing comprehensibilityo# the code3

enum shape9circle* sEuare* triangle:8

enum color9red* blue* green* yellow:8

In C$$ the tag name shape and color becomes

new types names3 By using these tag names wecan declare new "ariables3 Shape ellipse8 QQ ellipse is o# type shape

Color bacground8 QQ bacground is o# type color


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!numeration

Statement . Color bacground blue8

Statement L Color bacground T8

Statement G Color bacground 9color: T8

Statement U Int c blue8


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Storage Classes

In addition to data types* "ariable alsoha"e storage classes3

% storage class species the li#e time

and "isibility with in the program3

&here are #our storage classes %utomatic

!xternal Static

egister


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Deri"ed Data types

%rray Character %rray

9)ow will you declare a character array

that store xyA< V :

Functions

Pointer Statement .@ Char const ptr.

WOOD


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