Methods that subclasses should implement are declared abstract Instances of the subclasses are created, but no instances of the superclass Clever Factoring
OOP
All instance variables can be uniformly accessed by subclasses and superclasses c Objects of a subclass can be treated like objects of their superclass d None of
jhtp TIF
What are properties of instances of class Circle? Use the keyword super to call the superclass constructor A subclass inherits methods from a superclass
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X is the subclass, and Y is the superclass 2 Which visibility modifier allows the data members of a superclass to be accessible to the instances of subclasses?
Ch QC thEd
X is the subclass, and Y is the superclass 2 Which visibility modifier allows the data members of a superclass to be accessible to the instances of subclasses?
th Ed Ch QC
Inheriting from the Superclass ❑ Subclasses inherit from the superclass: ▫ All public methods that it does not override ▫ All public instance variables
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Class EPuzzle is a subclass of class Puzzle • Class Puzzle is a superclass of class EPuzzle • An EPuzzle object has – its own instance variable numMoves and
Inheritance up
9/17/12 2 Subclasses Inheritance Subclass has a super class or “parent” class Describes the format of a folder (instance, object) of the class /**
presentation
Sub type vs subclass Visible to subclasses and types in same package ○ some object, but with the current object viewed as an instance of the superclass
inheritance
To implement subclasses that inherit and override superclass methods Subclass objects automatically have the instance variables that are declared in the ...
Subclasses inherit from the superclass: ? All public methods that it does not override. ? All public instance variables. ? The Subclass can.
In other words every class
X is the subclass and Y is the superclass. 2. Which visibility modifier allows the data members of a superclass to be accessible to the instances of subclasses
instance of B. ? then B is a superclass of A a subclass graph need not be a tree a class may have multiple superclasses of#35# ece#627#winter#'13#.
Polymorphism and Subclasses. • A subclass instance is a superclass instance. – Polymorphism still works! – BankAccount ba = new CheckingAccount();.
Subclass inherits from superclass: all fields (state) and methods (behavior) Ability to replace any instance of a superclass with.
Methods that subclasses should implement are declared abstract. Instances of the subclasses are created but no instances of the superclass.
Superclass / Subclass. • Inheritance. • Overriding. • "isa" -- an instance of a subclass isa instance of the superclass. The subclass is just a refined form
Putting common code in a superclass then having subclasses inherit from it - they get all of its instance variables and methods
Only declare instance variables that are not part of the superclass objects A subclass inherits all methods that it does not override
The subclass inherits state and behavior in the form of variables and methods from its superclass The subclass can use just the items inherited from its
Subclasses inherit from the superclass: ? All public methods that it does not override ? All public instance variables ? The Subclass can
Therefore a subclass is a specialized version of a superclass It inherits all of the instance variables and methods defined by the superclass and add its
A subclass inherits the methods of its superclass The instance variables declared in the superclass are present in subclass objects balance =
The subclass exhibits the behaviors of its superclass and superclass constructor to initialize the instance variables inherited from the superclass
Enhance with new capabilities – Subclass extends superclass • Subclass – More specialized group of objects – Behaviors inherited from superclass
A subclass inherits all the methods and all the instance variables of the superclass and additionally it can have its own methods and instance variables 8 2
Subclass inherits from superclass: all fields (state) and methods (behavior) • You can use an object of the sub-class any place you expect a super-class
Putting common code in a superclass, then having subclasses inherit from it - they get all of its instance variables and methods.
Is a subclass an instance of its superclass?
A subclass inherits the methods and instance data of its superclasses, and is related to its superclasses by an is-a relationship. For example, if subclass P inherits from superclass Q, and subclass Q inherits from superclass S, then an instance of P is an instance of Q and also (by transitivity) an instance of S.Is a subclass an object of superclass?
ANS: b. A superclass object is a subclass object.Can subclasses access superclass instance variables?
Subclasses inherit public methods from the superclass that they extend, but they cannot access the private instance variables of the superclass directly and must use the public accessor and mutator methods.- Definition: A subclass is a class that derives from another class. A subclass inherits state and behavior from all of its ancestors. The term superclass refers to a class's direct ancestor as well as all of its ascendant classes.
Chapter 9