7/26/2019 Lecture03 (1).ppt

1/25

Object Oriented

Programming

Using C++ Programming

Language

7/26/2019 Lecture03 (1).ppt

2/25

RECAP

Information hiding

Encapsulation

Implementation

Interface

Messages

Abstraction

Student

7/26/2019 Lecture03 (1).ppt

3/25

Lecture #

Classes! Abstract "ata $pes!

Comparison %ith Structures

7/26/2019 Lecture03 (1).ppt

4/25

Classes

Objects ha&ing same data andbeha&ior belong to same class'

Student

7/26/2019 Lecture03 (1).ppt

5/25

E(ample ) Class

Circle is an closed o&al shape

S*uare is a closed rectangular shape

Line is open shape %ith start andending point

Each one is a shape

+e sa$ these objects are instancesofthe shape class

7/26/2019 Lecture03 (1).ppt

6/25

Inheritance

Idea of classes leads to idea ofinheritance'

Classes can be di&ided intosubclasses

Car ruc, -usMotoc$cl

e

.ehicle

-ase Class

"eri&ed Class

7/26/2019 Lecture03 (1).ppt

7/25

Reusabilit$

Inheritance e(tends reusabilit$

Subclasses can add more functionalit$to the base class %ith out modif$ing it'

E(ample/

A Class e(t0ileReader can be e(tendedto an 1ML0ileReader subclass'

7/26/2019 Lecture03 (1).ppt

8/25

Pol$morphism

23 4 5

"2 3 "6 4 " 7"2! "6 and " are

8

Shape'"ra%9:

"istance/Int 0eet0loat Inches

7/26/2019 Lecture03 (1).ppt

9/25

O&erloading

If %e use Operators to achie&ePol$morphism it is called operatorO&erloading

3 ! ;! 4! suall$ used to store onl$ "ataInformation'

Classes stores both data and functionalit$

7/26/2019 Lecture03 (1).ppt

13/25

A Simple Structure

struct part

7

int modelnumberint partnumber

?oat cost

8

7/26/2019 Lecture03 (1).ppt

14/25

"e=ning a Structure DS$nta(

struct part

7

intmodelnumber

int

partnumber?oat cost

8

e$%ord ag D "atat$pe Fame

"e=nitionboundar$

Members

Semicolon!ermination

S$m

7/26/2019 Lecture03 (1).ppt

15/25

"e=ning a structure &ariable

Similarl$ as %e de=ne int or

A ?oat &ariable

$pe &arFamee'g' Part partA

Memory

G

2H2H2H2H

2H2H2H2H

2H2H2H2H

2H2H2H2H22H2H2H2

22H2H2H2

22H2H2H2

22H2H2H2HHH22H22

HHH22H22

HHH22H22

HHH22H22

G

struct part

7int modelnumberint partnumber?oat cost

8

7/26/2019 Lecture03 (1).ppt

16/25

Comple( Structures

Structures %ithin structure

Accessing members &ariables Line Line1

Cout Line1'-'(;cord

struct point7int (;cordint $;cord8

struct Line7Point APoint -8

LinePoint (;cord $;cord

Point (;cord $;cord

7/26/2019 Lecture03 (1).ppt

17/25

InitialiJation of structure

"e=nation onl$

Line LineA- 7not recommended8

Empt$ or Kero &alued

Line LineA- 4 7H8 7recommended8

InitialiJation %ith &alues

Line LineA- 4 77!68!7!588

Assigning &alue direct to member&ariable

LineA-'PointA'$;cord 4

7/26/2019 Lecture03 (1).ppt

18/25

Structures and Classes

Structures are usuall$ used to hold data onl$ classes hold both data and functions

In C33 structures can in fact hold both dataand functions

Major diBerence bet%een class and astructure is that in a class members arepri&ate b$ default %hile in a structurethe$are public b$ default'

7/26/2019 Lecture03 (1).ppt

19/25

Enumerations

EnumerationdiBerent approach to de=ning $our o%ndata t$pe.

+e can %rite a perfectl$ =ne program %ithoutenumeration but enumeration pro&ides a lot of ease in

programming b$ simplif$ and clarif$ing programmingcode'

Enumerated types works when you know in advance a

fnite list o values'

7/26/2019 Lecture03 (1).ppt

20/25

7/26/2019 Lecture03 (1).ppt

21/25

Clarit$ of code %ith enumsintda$2!

s%itch 9da$2:

7

case 2/

G'

brea,

case 6/

G'

brea,

case /

G'brea,

GG

8

da$sNofN%ee,da$2!s%itch 9da$2:

7

case SA/

G'

brea,

case S>F/

G'

brea,

case MOF/

G'

brea,

GG

8

7/26/2019 Lecture03 (1).ppt

22/25

S$nta( of declaring Enums

Enumdeclaration de=nes the set of allnames that %ill be permissible &alues ofthe t$pe'

Permissible &alues are called enumerators'

7/26/2019 Lecture03 (1).ppt

23/25

Enumeration

Enumerations internall$ treated as integers'

-$ default in enum declaration! the =rstenumerators integer &alue is H! the second

&alue 2! and so on' +e can also change the starting inde( or

number of enums' e'g'

enum Suit 7 clubs42! diamonds! hearts!spades 8

7/26/2019 Lecture03 (1).ppt

24/25

Another E(ample

enum direction 7 north! south! east!%est 8

direction dir2 4 south

cout dir2

C33 IDO treats &ariables of enum t$pesas integers! so the output %ould be 2

7/26/2019 Lecture03 (1).ppt

25/25

T U A