Questions and Answers
What does polymorphism enable you to do?
program in the general
Which of the following is false about interfaces?
What does polymorphism specifically enable the creation of programs that handle?
a wide variety of classes in a general manner
Polymorphism allows classes to be added with little or no modifications to the generic portion of a program.
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When used correctly, polymorphism will never require changes to be made to any part of the program.
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Unfortunately, polymorphic programs make it difficult to add new capabilities to a system.
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Polymorphism enables objects of different classes that are related by a class hierarchy to be processed generically.
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The major drawback to polymorphically designed programs is that they do not take into account the future addition or deletion of classes.
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During what process does polymorphism allow for specifics to be dealt with?
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What does polymorphism involve?
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Polymorphism allows the addition of classes providing they were at least considered during program development.
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When a request is made to use a derived-class-object method through a base-class reference, C# polymorphically chooses the correct overridden method in the appropriate derived class that's associated with the object.
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Polymorphism allows you to command a wide variety of objects even if you do not know the objects' types.
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Polymorphism helps promote software extensibility.
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What best describes the relationship between base class and derived class types?
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If an app needs to perform a derived-class-specific operation on a derived class object referenced by a base class variable, the app must first cast the base class reference to a derived class reference through a technique known as _________.
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If a derived class reference is assigned to a base class variable, the variable must be cast back to the derived class before any derived class methods can be called with it.
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What may not be instantiated?
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The abstract methods and properties of a class do not provide an implementation.
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Concrete classes provide implementations for every method and property they define.
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You may define implementations for abstract methods to act as default implementations.
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All methods in an abstract class are inherently abstract.
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An abstract base class can be used to declare references.
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The abstract keyword has the same effect as the virtual keyword.
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An abstract class may be derived from another abstract class.
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Objects of abstract base classes can be instantiated.
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Study Notes
Polymorphism Overview
- Polymorphism allows programming in a generalized manner, enabling flexibility in handling various classes.
- It facilitates the use of different related classes generically, enhancing code extensibility.
- The addition of new classes can be achieved with minimal changes to the existing program architecture.
Interfaces
- An interface defines a collection of methods that must be implemented without providing default implementations.
- Incorrectly, it is believed interfaces provide default implementations for methods.
True/False Statements
- Polymorphism enables classes to be added with little or no modifications to existing code: True.
- While polymorphism aims to be adaptive, certain parts may require changes when the new class directly interacts with existing logic: False.
- Polymorphic programming simplifies adding new capabilities: True.
- Polymorphism allows objects from different classes in the same hierarchy to be processed without needing to know the specific class type: True.
Execution and Message Handling
- The specifics of class behaviors are resolved during program execution.
- A single message can be sent to various objects, each interpreting the message based on its class-specific logic.
Base and Derived Classes
- A reference of a derived class can be assigned to a base class variable; the reverse is not true.
- When needing to call derived class methods with a base class reference, it must first be downcast to the appropriate derived class type.
Abstract Classes
- Abstract classes cannot be instantiated directly and are typically used as base classes.
- They can contain abstract methods that do not have implementations, unlike concrete classes that fully implement methods.
- It is syntax error to provide implementations for abstract methods, reinforcing that they are meant to be overridden in subclasses.
Key Characteristics
- Not all methods in an abstract class are abstract; some may be concrete with implemented functionality.
- Abstract classes can be effectively utilized for declaring references, allowing flexibility in method calls.
- The abstract and virtual keywords serve distinct roles: abstract methods require overrides, while virtual methods provide default implementations.
General Insights
- Polymorphic programming enhances software extensibility and adaptability, supporting future class additions seamlessly.
- The relationship between base and derived classes is crucial for polymorphic behavior, enabling a flexible programming environment.
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Description
Test your understanding of polymorphism and interfaces in programming with this quiz. Explore key concepts and true/false statements to reinforce your knowledge about code extensibility and the role of interfaces. Perfect for students looking to grasp object-oriented programming principles.
