Deck 8: Object-Oriented Programming

Question 1

Encapsulation is the ability to make important object features available while hiding nonessential details, thereby focusing on the outside view of an object.

Answer 1

False

Question 2

By default, any properties and methods that you define in a class are public , which means they can be accessed from outside the class.

Answer 2

True

Question 3

With inheritance, it is possible to build an entire family of classes consisting of parents, children, grandchildren and siblings.

Answer 3

True

Question 4

Encapsulation allows the internal representation of objects to be hidden from view outside the object definition.

Question 5

The problem with using global variables is that they work against object-oriented programming principles.

Question 6

Polymorphism can be implemented within Ruby by assigning different names to different methods.

Question 7

A variable with a global scope can be accessed only within the method it was created in.

Question 8

Abstraction is implemented through classes and includes the specification of both properties and methods.

Question 9

When included in a class definition, the initialize method is automatically executed any time an object is instantiated.

Question 10

You should assign variables the lowest level of scope needed to provide the required access.

Question 11

Polymorphism is the process by which one class is derived from another class.

Question 12

Abstraction involves the restriction of access to one or more of the properties and methods defined within a class.

Question 13

To use the public , private , and protected keywords, you must place them on the same line as the property or method definitions for which you wish to specify access.

Question 14

With inheritance, the derived class, sometimes referred to as the child class, inherits all of the properties and methods of the parent class.

Question 15

Access to any properties or methods that are defined after the occurrence of the public , private , and protected keywords is governed by that keyword, which remains in effect until either the end of the class is reached or a different level of encapsulation is specified.

Question 16

Local variables are accessible throughout a Ruby program and have an unlimited scope. Every class in the program is allowed to access them.

Question 17

Polymorphism is the ability to define objects and methods in different forms.

Question 18

Inheritance makes program code more reliable by limiting access to just the areas within the program where access is required, which helps prevent accidental modification or execution.

Question 19

To instantiate an object and initialize it with one or more properties in a single step you must use the initialize method.

Question 20

One limitation of inheritance is that you cannot modify the inherited properties and methods or add new ones to customize child classes.

Question 21

With ____ you can build an entire family of classes made up of parents, children, grandchildren, siblings, etc.

A) Polymorphism
B) Encapsulation
C) Abstraction
D) Inheritance

Question 22

____ is implemented through classes and includes the specification of both properties and methods.

A) Inheritance
B) Encapsulation
C) Abstraction
D) Polymorphism

Question 23

Which of the following methods can be used to instantiate and initialize and object in a single step?

A) open
B) new
C) initialize
D) init

Question 24

Access specified by the public, private or protected keywords, remains in affect ____.

A) Only until the statement that following it is executed.
B) Only until the methods in which it is defined is executed.
C) Until either the end of the class is reached or a different level of encapsulation is specified.
D) None of the above

Question 25

By creating objects based on Ruby's built-in classes, you instantly get access to all the predefined methods that Ruby defines for those objects.

Question 26

To control access to the properties and methods within a class, you insert the ____ keyword into the class.

A) public
B) private
C) protected
D) All of the above

Question 27

____ is the process by which one class is derived from another class.

A) Inheritance
B) Encapsulation
C) Abstraction
D) Polymorphism

Question 28

____ is the ability to define objects and methods in different forms.

A) Polymorphism
B) Encapsulation
C) Abstraction
D) Inheritance

Question 29

It is sometimes helpful to increase the scope of the variables to allow them to be referenced by all the methods in that class definition.

Question 30

The ____ keyword restricts the access of any specified properties or methods defined within the object itself.

A) public
B) private
C) protected
D) closed

Question 31

____ involves the restriction of access to one or more of the properties and methods defined within a class.

A) Inheritance
B) Encapsulation
C) Abstraction
D) Polymorphism

Question 32

A variable with a ____ scope can be accessed only within the scope that it was created in.

A) local
B) global
C) instance
D) class

Question 33

One way to implement ____ within Ruby is to assign the same name to different methods.

A) Encapsulation
B) Polymorphism
C) Abstraction
D) Inheritance

Question 34

One of the limitations of working with Ruby's built-in classes is that you can read but not modify property values.

Question 35

An advantage of chaining methods together is that you can perform complex tasks with a minimal amount of programming code.

Question 36

____ is an object-oriented feature that provides the ability to make important object features available while hiding nonessential details.

A) Abstraction
B) Encapsulation
C) Inheritance
D) Polymorphism

Question 37

The ____ keyword makes any specified properties or methods available throughout the program.

A) public
B) private
C) protected
D) closed

Question 38

The ____ keyword restricts the access of any specified properties or methods to objects of the same class or objects of subclasses of the class.

A) public
B) private
C) protected
D) closed

Question 39

Which of the following types of variables is supported by Ruby?

A) Local
B) Global
C) Instance
D) All of the above

Question 40

One limitation of working with Ruby classes is that Ruby does not permit programmer's to customize the language to meet programmer needs.

Question 41

Which of the following statements is a benefit of using one of Ruby's built-in classes?

A) You simplify code development by eliminating the need to re-solve already solved programming tasks
B) You instantly get access to all of the pre-defined properties in that class.
C) You instantly get access to all of the pre-defined methods in that class.
D) All of the above

Question 42

@occurrences is an example of a(n) ____ variable.

A) local
B) global
C) instance
D) class

Question 43

Class variables begin with the ____ character.

A) @
B) @@
C) $
D) _

Question 44

Instance variables begin with the ____ character.

A) @
B) @@
C) $
D) _

Question 45

____ variables are accessible throughout a Ruby program and have an unlimited scope. Every class in the program is allowed to access them.

A) Local
B) Global
C) Instance
D) Class

Question 46

Local variables can begin with which of the following characters?

A) @
B) @@
C) $
D) _

Question 47

The following statements provide an example of ____ methods together. testArray = [1, 2, 3, 4, 5] puts testArray.sort.reverse.inspect

A) linking
B) chaining
C) connecting
D) binding

Question 48

Which of the following lists reflects a left-to-right increase in variable scope?

A) local, global, class, instance
B) local, class, instance, global
C) local, instance, class, global
D) instance, class, local, global

Question 49

____ variables are similar to instance variables, except they are accessible to all the instances of the same class, which makes it easier to make repeated references to variables.

A) Local
B) Global
C) Class
D) None of the above

Question 50

Global variables begin with the ____ character.

A) @
B) @@
C) $
D) _