Chapter 1

Question 1

Encapsulation

Answer 1

Encapsulation is the packing of data and functions into a single component.

Question 2

Object

Answer 2

An instance or manifestation of an object class.

Question 3

Class

Answer 3

may be thought of as the blueprint or pattern; the object itself is the thing created from that blueprint or pattern.

Question 4

Instantiated.

Answer 4

When an object (an instance of a class) is created, it is said to be instantiated.

Question 5

Class attributes

Answer 5

Class attributes or Class Variable.
Belong to class and not an object

Question 6

object attributes (or instance attributes).

Answer 6

We use the convention that any attribute is assumed to be an instance attribute unless we explicitly call it a class attribute.

Question 7

Class method

Answer 7

controls access to the class variables and also performs any tasks that might have classwide effects rather than merely objectwide.

Question 8

Inheritance

Answer 8

Inheritance is a relation between two classes. A child class inherits all the features of its parent class. Methods from the parent can be overridden in the child and new logic can be added.

Question 9

Subclass

Answer 9

When a class B inherits from a class A, we say that B is a subclass of A.

Question 10

Superclass

Answer 10

When a class B inherits from a class A, we say that A is the superclass of B.

Question 11

(MI)Multiple Inheritance

Answer 11

Ruby does not allow.

Question 12

What Is Polymorphism?

Answer 12

??

Question 13

Module?

Answer 13

A module is a collection of methods and constants that is external to the Ruby program. It can be used simply for namespace management, but the most common use of a module is to have its features “mixed” into a class (by using include). In this case, it is used as a mixin.

Question 14

Raise

Answer 14

??

Question 15

Ensure

Answer 15

??

Question 16

include (module)

Answer 16

The module’s methods become available as instance methods.

Question 17

extend(module)

Answer 17

The module’s methods become available as class methods.

Question 18

Load and require

Answer 18

A load operation reads a file and runs it in the current context so that its definitions become available at that point. A require operation is similar to a load, but it will not load a file if it has already been loaded.

Question 19

Super

Answer 19

Call the parent method.

Question 20

Alias

Answer 20

??

Question 21

singletons

Answer 21

They belong solely to that object and have no effect on its class or superclasses.