Chapter 10 Classes and Objects

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Chapter 10 Classes and Objects
CS240-Intermediate Programming
Created by Andrew StaugaardModified by Dr.
Martins

• Chaminade University of Honolulu
• Department of Computer Science

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Definitions

• A class provides the foundation for creating
  specific objects, each of which shares the
  general attributes, or characteristics, and
  behavior of the class.
• At the abstract level, a class can be described
  as an interface that defines the behavior of its
  objects.
• At the implementation level, a class is a
  syntactical unit that describes a set of data and
  related operations that are common to its
  objects.

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Chapter 10

• CLASS DECLARATION FORMAT
• class name
• //FUNCTION MEMBERS
• public
• Function prototypes go here.
• //DATA MEMBERS
• private
• Variable definitions go here.
• //END CLASS

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Chapter 10

• The public class functions form the interface to
  the class and are accessible from outside the
  class.
• Public functions are used to provide access to
  and manipulate the private class members.
• A private class member is only accessible within
  the class by functions of the same class.

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Encapsulation

• Encapsulation means to package data and/or
  operations into a single well-defined programming
  unit.

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Information hiding

• Information hiding means that there is a binding
  relationship between the information, or data,
  and its related operations so that operations
  outside the encapsulated unit cannot affect the
  information inside the unit.

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Unified Modeling Language

• The Unified Modeling Language, or UML, is a
  technique for analyzing and designing
  object-oriented software.

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Chapter 10

• UML diagram for a SavingsAccount class

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Object

• An object is an instance, or specimen, of a given
  class.
• An object of a given class has the structure and
  behavior defined by the class that is common to
  all objects of the same class.

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Chapter 10

• Object Definition Format
• class name object name

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A function implementation

• A function implementation is the definition of
  the function that includes the function header
  and the body of the function.

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Chapter 10

• Format for a Function Implementation
• return type class name function name
  (parameter listing)
• //BODY OF FUNCTION GOES HERE
• //END FUNCTION

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Constructors

• A constructor is a special class function that is
  used to initialize an object automatically when
  the object is defined.

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Constructor Format
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Chapter 10

• All the member functions of a class carry with
  them an invisible pointer, called this, that
  points to the object that called the function.

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Access Functions

• An access function, sometimes called a get
  function, is a function that returns only the
  values of the private members of an object.

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Messages

• A message is a call to a member function.

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Chapter 10

• A type cast converts data of one type to a
  different type, temporarily.
• You can convert data of one type to another type
  by preceding the data variable/expression with
  the type to convert to within parentheses like
  this
• winPercent (double)wins/(wins losses) 100

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Project Files

• A project file identifies the files that need to
  be compiled and linked to create a given
  executable program.

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A multi-file Project