oops note.doc

8/10/2019 oops note.doc

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OOPS 1

INTODUCTION TO OOPS

C++ programming is object oriented .

In C++, the unit of programming is the class from which the objects

are eventuall created.

C++ programmers concentrate on creating their own user defined data

tpes called classes.

C++ is an e!tensive version of C language.

C++ is derived from C.

C++ name is named b "ic# $arcitti

C++%s OOP aspect was inspired in earl 1&'(%s b )jarne Stroustrup.

1. What is class?Declaration of class?

* class is a collection of Objects. * Class is a collection of properties ,behavior with e!istence

* class is a user defined data tpe which hold both data and

function.

he data included in the class i.e, the internal data is called the

member data and function included in the class are called

member function.

e! fruit mango-

fruit is the class and mango is the object.

eneral form of class declaration isclassclass/name

{

private:

variable declaration-

function declaration-

pulic:

variable declaration-

function declaration-

0-

Class #eword.

Class!na"euserdefined data tpe.

Class is similar to structure in c

$$C2


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OOPS 3

#. What is $estructor? %o& it is invo'e$?

* destructor is a special member function of the class.

It deallocate memor space.ie, It is used to destro the objects

that have been created b a constructor he destructor name is the same as the class name but is

preceded b a tilde456.

2! 5pen46 77destructor

8

0

* destructor is defined under public section of the class.

* destructor never ta#es an argument nor does it return an

value .

It will be invo#ed implicitl b the compiler upon e!it from

the program to clean up storage that is no longer accessible.

(. %o& the o$) of "e"er fuction of a class is &ritten?

* function which is defined or declared inside the class is

called as member function.

$ember function can be defined in two places.

Outside the class definition.

Inside class definition.

Outsi$e the class $efinition

$ember function that are declared inside a class have to be

defined separatel outside the class.

he general form of a member function $efinition outsi$e the

class is:

*eturn!t)pe class!na"e::function!na"e+ar,u"ent $eclaration-

{

unction o$)/

0

classpen

8

private

int a,b-

public

$$C2


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OOPS 9

void read46 - 77member function declared

void dis46 - 77 member function declared

0-

void penread46

8

cin::a::b-

0

void pendis46 defined outside the class

8

cin::a::b-

0

void main46

8

pen p- p.read46-

p.dis46-

0

Insi$e the class $efinition

;unction definition inside the class

he general form of a member function $efinition insi$e the

class is:

*eturn!t)pe function!na"e+ar,u"ent $eclaration-

{ unction o$)/

0

classpen

8

private

int a,b-

public

void read46 77member fuction

8 cin::a::b-

0

void dis46 77member function inside the class

8

Cout


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OOPS =

void main46

8

pen p-

p.read46-

p.dis46-

0

. Define class an$ o2ect. ?

class+refer 3no:1-

o2ects

Objects are primar run>time entities.

Objects have some properties ,behavior with e!istence.

e! ?ame of Car,model,colour etc.

when a program is e!ecuted ever object will interacts with each other

b sending messages.

*n object is a specimen of a class.

4. What are the enefits of o2ect oriente$ pro,ra""in,@

hrough inheritance, we can eliminate redundant code and e!tend the

use of e!isting classes. It is eas to partition the wor# in a project based on objects.

Object>oriented sstem can be easil upgraded from small to large

sstems.

Software comple!it can be easil managed.

esser maintenance cost.

5. 67plain the features of o2ect oriente$ pro,ra""in,?

2mphasis is on data rather than procedure.

Programs are divided into what are #nown as objects. Aata is hidden and cannot be accessed b e!ternal functions.

Objects ma communicate with each other through functions.

;ollows bottom>up approach in program design.

$$C2


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OOPS B

8. 67plain $efault constructors or constructor?

* constructor that accepts no parameters is called the default

constructor.

It is used to initialies the object of a class.

* default constructor initialie the data members with no arguments.

general form of the default constructor is.

class user/define/name

8

private

>>>>>>>>>>>>

>>>>>>>>>>>>>

public

//////

//////user/defined name4677 default constructor

8

077with no arg

/////////////

/////////////

0/

* statement such as

* a-

invo#es the default constructor of the compiler to create the object Da%.eg

classpen

8

private

int a,b-

public

pen46 77constructor

8

aE1(-bE3(-

0

void dis46 77member function

8

Cout


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OOPS F

void main46

8

pen p-

p.dis46-

getch46-

0

9. What are $estructor in C? &hat are its use.

Destuctor+refer 3no:#-

It release memor space for future use.

new is used to allocate memor in the constuctors. Aelete is used to free that memor.

;. What are Constructors? e7plain its characteristics?

* member function with same name as its class is called as

constructor and it is used to initialie the object of that class

tpe with a legal initial value.

Constructor is the first member function.

Characteristicts

It has the same name as that of the class it belongs. Constuctor is e!ecuted when an object is declared.

It is automaticall called when an object is created of that

class.

Constructor have neither return value nor void .

he main function of constructor is to initialie objects and

allocate appropriate memor to objects.

Constuctor are e!ecute implicitl the can be invi#ed

e!plicitl.

1


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OOPS G

{

unction o$)/

0

67:

Classpen

8

private :

int a,b-

pulic:

void read46-

void displa46-

0-

void penread46

8

cin::a::b- 0

void pendispla46

8

cout


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OOPS '

*ll variables must be declared before the are used in the

program.

1#. Define an$ e7plain a cop) constructor@

* cop constructor is a special member function of the

form class/name4class name Hptr6 Ptr>pointer to the object.

his tpe of function is used when the compiler has

create a temporar object of a class object.

he compiler will use the cop constructors whenever

ou initialie an instance using values of another

instance of same tpe.

2! pen p- 77default constructor pen 4p6- 77cop constructor invo#ed

Pro,ra"

Class pen

8

private

int a,b-

public

pen4int !, int 6 77constructor with argument

8

aE!-

bE-

0

Pen4pen H ptr6

8

aEptr.a-

bEptr.b-

0Joid dis46

8

Cout


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10/38

OOPS 1(

0-

main46

8

Pen p4B(6-

p.dis46-

0

#. 67plain the evolution of oops?

he object oriented programming language language was

developed at * H )ell laboratories in earl 1&'(%s b )jarnce

Strostrup.

Object oriented programming is an approach to program

organiation and development that attempts to eliminate some

of the pit falls of conventional programming b incoparating

the best of structured programming features several powerful new concepts.techniues such as

modular,topdown,bottom up and structured programming.

O2ect@oriente$ pro,ra""in,

Proce$ure oriente$

Bsse"l) lan,ua,e

>achine lan,ua,e

1=< +Ainar) lan,ua,e-

$$C2


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OOPS 11

(. Arin, aout the enefits an$ appilication of o2ect oriente$

pro,ra""in,.

Aenefits+refer 3no:4-

Bpplication of o2ect@oriente$ pro,ra""in,

"eal time sstem

Simulation and modeling

Object>oriented databases

Kperte!t,hpermedia and e!perte!t

*I and e!pert sstems

?eural networ#s and parallel programming

CI$7C*A7C*$ sstem

. Distin,uish et&een proce$ure oriente$ lan,ua,es an$ o2ect

oriente$ lan,ua,es?

*efer part B+ 3no:5-

Proce$ure oriente$ pro,ra""in,

Conventional programming,using highlevel languages

2mphasis is on doing things

arge programs are divided into small programs #nown as

functions

$ost of the functions share global data

Aata $ove openl around the sstem from function to

function.

;unction transform data from one form to another

$$C2


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OOPS 13

2mplos top>down approach in program design.

o2ect@oriente$ proce$ural

methods functions

objects modules

message argument

attribute variable

4.67plain the asic concepts of oops?

oop has few major components such as objects and classes.

)ased on the objects and classes the features ofinheritance,encapsulation,data abstraction,reusabilit and

polmorphism are implemented.

OA6CTS

object is a primar run time entit.

object is a logical entit that contains both data and code that

manipulate the data.

e!name of person,place etc.

CBSS

In oops the objects are members of classes. * class is a collection of objects which have similar

characteristics.

e! class car.

properties compan,model,color etc.

6NCBPSUBTION

$$C2


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OOPS 19

Lrappind up of data and function into a single unit.

Aata encapsulation is a stri#ing feature of a class.

DBTB 6NCBPSUBTION

*bstraction refers to the act of representing essential

features without including the bac#ground details ore!planations

he classes uses the concept of data abstraction.

IN%6*ITBNC6

Inheritance is the process b which objects of one class inherits

the properties of objects of another class.

he concept of inheritance provides the idea of reusabilit.

POE>O*P%IS>

Polmorphism is a gree# term.

It means the abilt to ta#e more than one form.

>ODU6@II

1.Define an$ e7plain Inheritance in oops?

Inheritance is the powerfull feature of oops.

Inheritance is the process b which objects of one class acuire

the properties of objects of another class.

he concepts of inheritance provides the idea of reusailit).

Inheritance is a mechanism which deriving a new class from

alread e!isting class.

)ase class is parent class and derived class is child class.

$$C2


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OOPS 1=

parent class

child class

base class

derived class

Inheritance of stu$ent class

Inheritance are mainl five tpes.

1.single inheritance

3.multiple inheritance

9.multilevel inheritance

=.hierarchical inheritance

B.hbrid inheritance

he derived class inherits some or all of the traits from the base

class.

* derived class with onl one base class is called sin,le

inheritance.

* derived class with several base classes is called "ultiple

inheritance.

$$C2

Student

?ame

*ddress

M Sem

;eesStipend

P Sem

;eesStipend


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OOPS 1B

Aeriving a class from another derived class is called "ultilevel

inheritance or repeate$ inheritance.

One class ma be inherited b more than one class is called

hierarchical inheritance.

he result will have both the multilevel and multiple

inheritance is h)ri$ inheritance .

#. Ariefl) e7plain an) four for"s of inheritance?

Inheritance are mainl five tpes.

1.single inheritance

3.multiple inheritance

9.multilevel inheritance

=.hierarchical inheritance

B.hbrid inheritance

he derived class inherits some or all of the traits from the base

class.


inheritance.

Aase class +parent class-

Derive$ class + chil$ class-

* derived class with several base classes is called "ultiple

inheritance.

$$C2

B

)


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OOPS 1F

Aeriving a class from another derived class is called "ultilevel

inheritance or repeate$ inheritance.

Aase class +parent class-

Inter"e$iate class


$$C2

* ) C

A

B

)

C


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OOPS 1G


hierarchical inheritance.* class derived in a heirachical order.


inheritance is h)ri$ inheritance.

$$C2

ABS6

A2"IJ2A ?A2"IJ2A 3A2"IJ2A1

ABS6

ABS6

D6*I6D1

D6*I6D


18/38

OOPS 1'

(. 67plain frien$ function ?

;riend function can access the private and protected datas of

a class. * friend function to a class ma be declared or defined

within the scope of a class definition.

he general snta! of a friend declaration is

St!frien$ return!t)pe user!$efine!na"e+ar,u"ents list-/

;riend function declaration inside the class.

2g

Class *)C8

private

//////////////

//////////////

public

//////////////

//////////////

friend void !4void6- 77declaration

0-

2!

class pen

8

private

$$C2


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OOPS 1&

int a,b-

public

pen46

8

aE(-bEB-

0

pen4int w,int 6

8

aEw-bE-

0

void read 46

8cin::a::b-

0

void dis46

8

cout


20/38

OOPS 3(

In friend class,an entire class is made a friend to another

class

Creating the friend class all the member function of the

friend class can access the private member data of another

class.

he general snta! of a friend class is

Class*

8

private

////

////

public

////

;riend class )

77friend class declaration class )

77actual definition of friend class second

8

///

///

0In the above snta! ) is a friend class of class * from the

class ),all the member of the class * can be accessed.

2!

Sum of two no

class *

8

privateint a,b,s-

public

void read46

8

cin::a::b-

$$C2


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OOPS 31

0

friend class )-

0-

class )

8public

void sum4* obj6

8

obj.sEabj.a+obj.b-

0

0-

void main46

8* a-

) b-

a.read46-

b.sum4a6-

0

4.67plain Sin,le inheritance?


inheritance.

eneral snta! for single inheritance definition is

Class base

8

////////////

////////////

$$C2


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OOPS 33

0-

Class derived public base

8

//////////////

//////////////

0-

he e!isting class or base class is called as direct

base class

?ewl formed class is called derived class.

he newl derived class had their own properties as well as

the can inherit all the properties of the base class.

+pen- Aase class +parent class-

+ Pencil-

Derive$ class + chil$ class- Sin,le inheritance

67: class pen

8

private

int a,b-

$$C2

B

)


23/38

OOPS 39

public

pen46

8

aE(-

bE1-

0

pen4int m,int n6

8

mEa-

nEb-

0

void read46

8

cin::a::b-

0void displa46

8

cout


24/38

OOPS 3=

0

void displa146

8

cout


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OOPS 3B

0-

Class derivedpublic base1,public base3

8

///////////

///////////

0-

$ultiple inheritance means that a derived class inherit the

members of several base classes.

4pencil6

4Pen6 4paper6

4"esult6

2!class pen

8

private

int a,b-

public

pen46

8

aE(-bE1-

0

pen4int m,int n6

8

mEa-

nEb-

$$C2

* ) C

A


26/38

OOPS 3F

0

void read46

8

cin::a::b-

0

void displa46

8

cout


27/38

OOPS 3G

public

paper46

8

eE(-

fE1-

0

paper4int ,intr6

8

Ee-

rEf-

0

void read346

8

cin::e::f-

0void displa346

8

cout


28/38

OOPS 3'

tEh-

0

void read346

8

cin::a::b::c::d::e::f-

0

void displa346

8

cout


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OOPS 3&

0-

Class derived1public base1

8

/////////////

/////////////

0-

Class derived3public derived 1

8

//////////

//////////

0-

he class derived1 is called intermediate class.

+Pen- Aase class +parent class-

+Pencil-

Inter"e$iate class


+Paper-

class pen

8

private

$$C2

B

)

C


30/38

OOPS 9(

int a,b-

public

pen46

8

aE(-

bE1-

0

pen4int m,int n6

8

mEa-

nEb-

0

void read46

8

cin::a::b-0

void dis46

8

cout


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OOPS 91

0

void displa146

8

cout


32/38

OOPS 93


hierarchical inheritance.* class derived in a heirachical order.

+Pen-

4pencil6

4boo#6

2! 4Paper6

class pen

8

private

int a,b-

public

pen46

8

aE(-bE1-

0

pen4int m,int n6

8

mEa-

nEb-

0

void read46

8cin::a::b-

0

void displa46

8

cout


33/38

OOPS 99

0-

class pencilpublic pen

8

private

int c,d-

public

pencil46

8

Pen46-

cE(-

dE1-

0

pencil4int m,int n,int o,int p6

8

pen4m,n6-oEc-

pEd-

0

void read146

8

cin::a::b::c::d-

0

void displa146

8

cout


34/38

OOPS 9=

pencil4int m,int n,int ,int r6

8

pen4m,n6-

Ee-

rEf-

0

void read346

8

cin::a::b::e::f-

0

void displa346

8

cout


35/38

OOPS 9B

0-

Joid main46

8

Pencil p-

Paper -

)oo# b-

p.displa146-

.displa346-

b.displa946-

getch46-

0

5. 67plain h)ri$ inheritance?


inheritance is h)ri$ inheritance.

pen paper

pencil

$$C2

ABS6

ABS6

D6*I6D1

D6*I6D


36/38

OOPS 9F

result

class pen

8

private

int a,b-

public

pen46

8

aE(-

bE1-

0pen4int m,int n6

8

mEa-

nEb-

0

void read46

8

cin::a::b-

0void displa46

8

cout


37/38

OOPS 9G

0

pencil4int m,int n,int o,int p6

8

pen4m,n6-

oEc-

pEd-

0

void read146

8

cin::a::b::c::d-

0

void displa146

8

cout


38/38

OOPS 9'

class resultpublic pencil,public paper

8

private

int g,h-

public

result46

8

gE(-

hE1-

0

result4int m,int n ,int o,int p,int ,int r,int s,int t6

8

Pencil4m,n,o,p6-

Paper4,r6-

sEe-tEf-

0

void read946

8

cin::a::b::c::d::e::f::g::h-

0

void displa946

8

cout

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