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Copyright © 2003 by Prentice Hall Computers: Tools for an Information Age Chapter 15 Programming...
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Transcript of Copyright © 2003 by Prentice Hall Computers: Tools for an Information Age Chapter 15 Programming...
Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
Computers:Computers:Tools for an Information AgeTools for an Information Age
Chapter 15Chapter 15Programming and Languages:Programming and Languages:
Telling the Computer What to DoTelling the Computer What to Do
22 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
ObjectivesObjectives
Describe what programmers do and do not doDescribe what programmers do and do not doExplain how programmers define a problem, Explain how programmers define a problem, plan the solution, and then code, test, and plan the solution, and then code, test, and document the programdocument the programList and describe the levels of programming List and describe the levels of programming languages: machine, assembly, high level, very languages: machine, assembly, high level, very high level, and naturalhigh level, and naturalDescribe the major programming languages that Describe the major programming languages that are in use todayare in use todayExplain the concepts of object-oriented Explain the concepts of object-oriented programmingprogramming
33 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
ProgrammingProgramming
Program – a set of detailed, step-by-step Program – a set of detailed, step-by-step instructions that directs the computer to do instructions that directs the computer to do what you want it to dowhat you want it to do
Programming language – a set of rules Programming language – a set of rules that provides a way of telling the computer that provides a way of telling the computer what operations to performwhat operations to perform
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The Programming ProcessThe Programming Process
Five main stepsFive main steps Defining the problemDefining the problem Planning the solutionPlanning the solution Coding the programCoding the program Testing the programTesting the program Documenting the programDocumenting the program
1212 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
Levels of LanguagesLevels of Languages
Lower-level languages – more like the 0s Lower-level languages – more like the 0s and 1s the computer itself usesand 1s the computer itself uses
Higher-level languages – more like the Higher-level languages – more like the languages people uselanguages people use
Divided into five generationsDivided into five generations
1313 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
Five Generations of LanguagesFive Generations of Languages
Machine languageMachine language
Assembly languagesAssembly languages
High-level languagesHigh-level languages
Very high-level languagesVery high-level languages
Natural languagesNatural languages
1919 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
Major Programming LanguagesMajor Programming Languages
FORTRANFORTRAN
COBOLCOBOL
BASICBASIC
RPGRPG
Visual BasicVisual Basic
CC
JavaJava
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Object-Oriented ProgrammingObject-Oriented Programming
Object – a self-contained unit that contains both Object – a self-contained unit that contains both data and its related functionsdata and its related functionsKey terms in object-oriented programmingKey terms in object-oriented programming Encapsulation – an object isolates both its data and Encapsulation – an object isolates both its data and
its related instructionsits related instructions Attributes – facts that describe the objectAttributes – facts that describe the object
Also called propertiesAlso called properties Methods – instructions that tell the object to do Methods – instructions that tell the object to do
somethingsomething Messages – an outside stimulus that results in the Messages – an outside stimulus that results in the
change of the state of an objectchange of the state of an object
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Using ObjectsUsing Objects
Programmers define classes of Programmers define classes of objectsobjects
The class contains all attributes that The class contains all attributes that are unique to objects of that classare unique to objects of that class
An object is an instance An object is an instance (occurrence) of a class(occurrence) of a class
Objects are arranged hierarchically Objects are arranged hierarchically in classes and subclassesin classes and subclasses
Subclasses are derived from classesSubclasses are derived from classes Inheritance – a subclass possesses Inheritance – a subclass possesses
all attributes of the class from which all attributes of the class from which it is derivedit is derived
Additional attributes can be coded in Additional attributes can be coded in the subclassesthe subclasses
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Activating the ObjectActivating the Object
A message is sent to the object, telling it to A message is sent to the object, telling it to do somethingdo something The object’s methods tell it how to do itThe object’s methods tell it how to do it
Polymorphism – each object has its own Polymorphism – each object has its own way to process the messageway to process the message For example, the class may have a Move For example, the class may have a Move
method, but each subclass implements that method, but each subclass implements that method differentlymethod differently
3030 Copyright © 2003 by Prentice HallCopyright © 2003 by Prentice Hall
Object-Oriented LanguagesObject-Oriented Languages
C++C++
JavaJava
C#C#
Visual BasicVisual Basic