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Questions and Answers
A class inherited from two or more levels up in the hierarchy is known as a?
A class inherited from two or more levels up in the hierarchy is known as a?
indirect base class
Inheritance is represented by a(n) ________ relationship.
Inheritance is represented by a(n) ________ relationship.
is-a
A _________ derived class cannot access the members of its base class.
A _________ derived class cannot access the members of its base class.
private
Which of the following statements is false?
Which of the following statements is false?
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A derived class can effect state changes in base class private members only through public, protected, internal methods provided in the base class and inherited into the derived class.
A derived class can effect state changes in base class private members only through public, protected, internal methods provided in the base class and inherited into the derived class.
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Inheritance is the process of building a class with object references of other classes.
Inheritance is the process of building a class with object references of other classes.
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A class that inherits from another class is referred to as the derived class.
A class that inherits from another class is referred to as the derived class.
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Every object of a base class is an object of that class's derived classes.
Every object of a base class is an object of that class's derived classes.
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A derived class is often larger and more general than its base class.
A derived class is often larger and more general than its base class.
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Multiple inheritance, widely used in C#, is the process of inheriting from more than one class.
Multiple inheritance, widely used in C#, is the process of inheriting from more than one class.
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The process of abstraction allows you to focus on the commonalities among objects in the system.
The process of abstraction allows you to focus on the commonalities among objects in the system.
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Which of the following pairs demonstrates the is-a relationship between the first and the second terms?
Which of the following pairs demonstrates the is-a relationship between the first and the second terms?
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Which of the following pairs demonstrates the has-a relationship between the first and the second terms?
Which of the following pairs demonstrates the has-a relationship between the first and the second terms?
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Identify which of the following examples could be considered a base class for the Computer class?
Identify which of the following examples could be considered a base class for the Computer class?
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Which of the following is not a base/derived class relationship?
Which of the following is not a base/derived class relationship?
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An advantage of inheritance is that:
An advantage of inheritance is that:
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A base class may have only one derived class.
A base class may have only one derived class.
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Members of a base class that are private are not inherited by derived classes.
Members of a base class that are private are not inherited by derived classes.
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Constructors are not inherited.
Constructors are not inherited.
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All classes in C# have object as either a direct or indirect base class.
All classes in C# have object as either a direct or indirect base class.
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An object of one class cannot be an object of another class.
An object of one class cannot be an object of another class.
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Derived classes provide the functionality and features inherited by base classes.
Derived classes provide the functionality and features inherited by base classes.
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A base class's constructors are inherited into its derived classes.
A base class's constructors are inherited into its derived classes.
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When a derived-class member overrides a base-class member, the base-class member can be accessed from the derived class by using the keyword ____________.
When a derived-class member overrides a base-class member, the base-class member can be accessed from the derived class by using the keyword ____________.
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Base class methods with this level of access cannot be called from derived classes.
Base class methods with this level of access cannot be called from derived classes.
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The protected members of a class may be accessed in their base class or any classes derived from that base class.
The protected members of a class may be accessed in their base class or any classes derived from that base class.
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A method must be declared __________ for it to be overridden by derived classes.
A method must be declared __________ for it to be overridden by derived classes.
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Which of the following classes is the root of the class hierarchy?
Which of the following classes is the root of the class hierarchy?
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Every class in C#, except __________, extends an existing class.
Every class in C#, except __________, extends an existing class.
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Overriding a method differs from overloading a constructor because:
Overriding a method differs from overloading a constructor because:
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To avoid duplicating code (and possibly errors), use _______, rather than _______.
To avoid duplicating code (and possibly errors), use _______, rather than _______.
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Consider the classes below, declared in the same file: class A { int a; public A() { a = 7; }} class B : A { int b; public B() { b = 8; }} A reference to class A can be treated as a reference to class B.
Consider the classes below, declared in the same file: class A { int a; public A() { a = 7; }} class B : A { int b; public B() { b = 8; }} A reference to class A can be treated as a reference to class B.
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Which base class members are inherited by all derived classes of that base class?
Which base class members are inherited by all derived classes of that base class?
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Which statement is true when a base class has protected instance variables?
Which statement is true when a base class has protected instance variables?
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Private fields of a base class can be accessed in a derived class
Private fields of a base class can be accessed in a derived class
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The first task of any derived-class constructor is to call its base-class constructor.
The first task of any derived-class constructor is to call its base-class constructor.
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A 'copy-and-paste' approach is a simple and efficient way from a software-engineering perspective of providing functionality that exists in other classes.
A 'copy-and-paste' approach is a simple and efficient way from a software-engineering perspective of providing functionality that exists in other classes.
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Using protected instance variables can cause derived-class methods to be written to depend on base-class implementation.
Using protected instance variables can cause derived-class methods to be written to depend on base-class implementation.
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When a derived class constructor calls its base class constructor, what happens if the base class's constructor does not assign a value to an instance variable?
When a derived class constructor calls its base class constructor, what happens if the base class's constructor does not assign a value to an instance variable?
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How can a derived class call a base class constructor?
How can a derived class call a base class constructor?
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When a program creates a derived-class object, the object constructor is the last constructor called and the first whose body finishes executing.
When a program creates a derived-class object, the object constructor is the last constructor called and the first whose body finishes executing.
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If a base class constructor is overridden, the original constructor can no longer be called explicitly by the derived class.
If a base class constructor is overridden, the original constructor can no longer be called explicitly by the derived class.
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When a base class method is overridden in a derived class, it is common to have the derived class version call the base class version and do some additional work.
When a base class method is overridden in a derived class, it is common to have the derived class version call the base class version and do some additional work.
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Which of the following statements is (are) true?
Which of the following statements is (are) true?
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Inheritance preserves the integrity of a base class.
Inheritance preserves the integrity of a base class.
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A key to improving the software development process is encouraging software reuse.
A key to improving the software development process is encouraging software reuse.
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To enhance performance and reduce errors, it's a good idea to make derived classes larger than they need to be.
To enhance performance and reduce errors, it's a good idea to make derived classes larger than they need to be.
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A base class is often designed by factoring out commonalities among a set of classes.
A base class is often designed by factoring out commonalities among a set of classes.
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When creating derived classes, you must use discretion in choosing the proper base class. Ideally, the base class will not contain excessive capabilities or information.
When creating derived classes, you must use discretion in choosing the proper base class. Ideally, the base class will not contain excessive capabilities or information.
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The default implementation of method ToString of object returns a string representing ________.
The default implementation of method ToString of object returns a string representing ________.
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The default Equals implementation determines:
The default Equals implementation determines:
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Method Equals will accurately compare any two objects.
Method Equals will accurately compare any two objects.
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Every object in C# has at least seven methods: Equals, Finalize, GetHashCode, GetType, MemberwiseClone, ReferenceEquals, and ToString.
Every object in C# has at least seven methods: Equals, Finalize, GetHashCode, GetType, MemberwiseClone, ReferenceEquals, and ToString.
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Study Notes
Inheritance Concept
- An indirect base class is a class inherited from two or more levels up in the hierarchy.
- Inheritance is represented as an "is-a" relationship, indicating a subclass's relationship to a superclass.
- A private derived class cannot access the members of its base class directly.
True/False Statements on Inheritance
- A base class object is not a derived class object; they represent different levels of hierarchy.
- A derived class can only change the state of base class private members via inherited public, protected, or internal methods.
- Inheritance involves extending class capabilities, whereas composition involves building a class with other object references.
- A derived class is typically not larger and more general than its base class; it is more specialized.
- Multiple inheritance, where a class inherits from more than one class, is not supported in C#.
- Constructors are specific to their class and are not inherited into derived classes.
Class Relationships
- An object of a base class cannot be an object of its derived classes due to the specificity of derived classes.
- Protected members of a base class can be accessed by derived classes, maintaining an internal hierarchy of access.
Method Overriding
- When overriding a base class method, use the "base" keyword to access the original member.
- A method must be declared as virtual to allow derived classes to override it.
- Overridden methods must maintain the same signature as the methods in the base class.
Access and Modifications
- Private fields in a base class can be accessed by derived classes only through public or protected methods.
- The first task of any derived-class constructor is to invoke its base class constructor to ensure proper initialization.
Software Design Principles
- Inheritance allows for the treatment of derived class objects as base class objects, promoting code reuse and reducing redundancy.
- A "copy-and-paste" approach is discouraged; inheritance is preferred to avoid code duplication.
- Classes should be minimal, containing only necessary capabilities, enhancing performance and reducing errors.
Object Class Hierarchy
- All classes in C# derive from the base class 'object', establishing a universal structure.
- The default implementation of the ToString method provides a string representing the namespace and the class name of the object.
Methods and Equality
- Equals determines if two references point to the same object in memory; it must be overridden to compare object contents accurately.
- Every C# object has at least seven methods, including Equals, GetType, and ToString, ensuring basic functionality.
Final Observations
- The integrity and functionality of a base class are preserved through inheritance, allowing for safe modifications in derived classes.
- Careful selection of the base class is necessary to avoid excessive capabilities, leading to cleaner and more maintainable code structures.
Studying That Suits You
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Description
Test your knowledge on Chapter 11 of the C# course with these flashcards. This quiz covers key concepts related to inheritance, base classes, and class hierarchy. Perfect for final exam preparation!
