Starting Out With Programming Logic & Design - Chapter14_Object Oriented Programming

7/24/2019 Starting Out With Programming Logic & Design - Chapter14_Object Oriented Programming

1/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley

Starting Out with Programming Logic & Design

Second Edition

by Tony Gaddis

Chapter 14:

Object-Oriented Programming


2/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-2

Chapter Topics

1.1 Procedural and !b"ect-!rientedProgra##ing

1.2 Classes

1.$ %sing the %ni&ied 'odeling (anguage to)esign Classes

1. Inheritance

1.* Poly#orphis#


3/19


14.1 Procedural and Object-Oriented

Programming

Procedural Progra##ing An early #ethod o& coding +here progra#s are centered on the

procedures or actions that tae place in a progra#

A procedure is si#ply a #odule

As progra# get larger and #ore co#ple, this #ethod leads to

proble#s

!b"ect !riented Progra##ing A ne+er #ethod o& coding +here progra#s are centered on

creating ob"ects

An ob"ect is a so&t+are entity that contains both data and

procedures he data in a ob"ect is no+n as the ob"ect/s &ields ariables,

arrays3

he procedures that are per&or#ed are called #ethods


4/19


14.1 Procedural and Object-Oriented

Programming

!b"ect !riented Progra##ing !!P3 addressesthe procedural proble# o& code4data separationby using t+o #ethods

Encapsulation 5 re&ers to the co#bining o& dataand code into a single ob"ect

)ata hiding 5 re&ers to an ob"ect/s ability to hide itsdata &ro# code that is outside the ob"ect

Another !!P bene&it is !b"ect 6eusability 7or ea#ple, an ob"ect that renders $) i#ages can

be used in #any di&&erent progra#s


5/19


14.2 Classes

A class is code that speci&ies the &ields and#ethods &or a particular type o& ob"ect A class is coded and contains #ethods and &ields

hin o& it lie a blueprint, such as a blueprint &or ahouse

It/s a detailed description

An ob"ect is then created &ro# the class It is an instance o& a class

hin o& it as the actual house


6/19


14.2 Classes

Creating a classClass ClassName

Field declarations and method declarations

End Class

he &irst line starts +ith Class, &ollo+ed by thena#e o& the class

he progra##er na#es the class &ollo+ing the sa#erules as na#ing ariables

he &ield declarations ariables3 and #ethods arede&ined +ithin the class


7/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-

14.2 Classes

Access speci&iersPrivateallo+s class #e#bers to be hidden &ro#

code outside the class

Publicallo+s &or all parts o& the code to access theclass #e#bers

It is co##on practice to #ae all &ields priate andto proide access only to those &ield through#ethods

here&ore, the #ethods should be public


8/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-!

14.2 Classes

Continued


9/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-"

14.2 Classes


10/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-1#

14.2 Classes

Inside Class (isting 1-$ he &ield are de&ined as priate to ensure data

hiding

he #ethods are public so they can be accessed by#ain

When the set #odules are called, a 8tring is passedinto the #ethod as an argu#ent and that alue isset to the priate &ield

When the get #odules are called, they si#plyreturn the alue o& the priate &ield


11/19


14.2 Classes


12/19


14.2 Classes


13/19


14.2 Classes

Inside Progra# 1-1 An ariable is created myPhone

myPhone is then used +ith the ey+ordNewtocreate the ob"ect in #e#ory

9alues are then stored in the ob"ect/s &ield bycalling the class #ethods

Call myPhone.setManufacturer(Motorola)

9alues are then displayed by calling the class#ethodsDislay !he manufacturer is " myPhone.#etManufacturer( )

he dot notation is used to associate an ob"ect +itha #e#ber o& the class


14/19


14.2 Classes

Constructor is a #ethod that is auto#aticallycalled +hen an ob"ect is created he purpose is to initiali:e an ob"ect/s &ields +ith

starting alues

A progra##er can +rite their o+n constructor toinitiali:e &ields

!r they can use the de&ault constructor that is

aailable +ith #ost progra##ing languages


15/19


14.3 $sing the $ni%ied &odeling 'anguage to

(esign Classes

he %ni&ied 'odeling (anguage %'(3 is astandard +ay o& dra+ing diagra#s thatdescribe ob"ect-oriented syste#s

Contains a set o& standard diagra#s &or graphicallydepicting !! syste#s

Figure 14-1)eneral la*out o%

a $&' diagram %or a class


16/19



(esign Classes

)ata type, #ethod para#eter, and accessspeci&ication notation is also added to a %'(diagra#

he data type speci&ies the data type o& the &ield orthe data type o& the #ethod

he #ethod para#eter speci&ies the para#eterariables and their data types

he access speci&ication indicates a ; &or public ora 5 &or priate


17/19



(esign Classes

Figure 14-14 $&' diagram %or the

CellPhoneclass +ith access

speci%ication notation


18/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-1!

14.4 ,nheritance

Inheritance allo+s a ne+ class to etend aneisting class, +hereas the ne+ class inheritsthe #e#bers o& the class it etends he superclass is the base class

he subclasses3 is the deried class

Figure 14-1!umblebees and

grasshoppers are specialied /ersions

o% an insect


19/19

Copyright 2010 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14-1"

14.5 Pol*morphism

Poly#orphis# allo+s you to create #ethods+ith the sa#e na#e in di&&erent classes thatare related through inheritance he progra##er has the ability to call the correct

#ethod depending on the type o& ob"ect that isused to call it

Poly#orphis# re&ers to an ob"ect/s ability to taedi&&erent &or#s

Starting Out With Programming Logic & Design - Chapter14_Object Oriented Programming

Documents

Transcript of Starting Out With Programming Logic & Design - Chapter14_Object Oriented Programming