OOP1 Classes

Question 1

Data representation

Answer 1

The concrete existing data types used to create an abstract data type

Question 2

Abstract data type

Answer 2

A user defined data type that has a properties of domain (data), and operations, also known as a class, which is independent of any particular implementation

Question 3

Constructor

Answer 3

An operation/method that instantiates a new variable/object of the class type

Question 4

Destructor

Answer 4

A method that destroys and deallocates the memory for an class instance variable

Question 5

Transformer/mutator

Answer 5

A method/operarion that changes the value of an instance of a class , or an object

Question 6

The state

Answer 6

The current state of an object / class instance

Question 7

Observer / accessor

Answer 7

A method/operation for accessing and observing the state or part of the state of a class instance/object

Question 8

Iterator method

Answer 8

A method that successively returns each item in a specific list of a class instance

Question 9

What does the specification of an ADT describe?

Answer 9

It specifies the data values and operations in an abstract way that can be given as documentation to both user and programmer

Question 10

What are the two things a programmer must do to implement an ADT?

Answer 10

1. Choose a concrete data representation using existing data types
2. Implement each of the allowable operations in terms of program instructions

Question 11

Class

Answer 11

A data type that is used to represent an abstract data type

Question 12

Why are classes useful?

Answer 12

An entity’s data and operations may not well be split apart, sometimes they act better as a single cohesive unit

Question 13

How are classes defined?

Answer 13

class keyword, {} definition block, containing declaration of data members and operations, with access modifiers, terminated by ;

Question 14

What is an access modifier?

Answer 14

A keyword used when declaring data types and methods for a class that specifies how they might be externally accessed

Question 15

What does private access modifier do?

Answer 15

Prevents implementations external to the class from accessing it

Question 16

When are constructors invoked?

Answer 16

They are invoked at instantiation

Question 17

What is a default constructor?

Answer 17

A parameterless constructor that is invoked implicitly as a default unless otherwise specified

Question 18

What is a class client?

Answer 18

Any implementation that creates and manipulates instances of a class

Question 19

What is the public interface?

Answer 19

The data and methods declared as public before private in the class definition

Question 20

What does public keyword mean?

Answer 20

Data and methods of the class can be accessed externally to the class

Question 21

Are class members public or private by default?

Answer 21

Private

Question 22

In terms of classes, how can structs be described?

Answer 22

Structs are classes that whereby all data members are public by default

Question 23

If an object is a variable, what is a class?

Answer 23

A type of

Question 24

Which C++ construct implements ADTs?

Answer 24

Class

Question 25

What distinguishes a class constructor from other members?

Answer 25

No function return type

Question 26

What is an active data structure?

Answer 26

One that contains both data and operations in a single cohesive unit

Question 27

Conceptually, classes have a “barrier” surrounding them. Its referred to as?

Answer 27

Abstraction barrier

Question 28

Abstraction barrier prevents what?

Answer 28

Private members and methods of classes being accessed by client code, and class members and methods from accessing outside its scope

Question 29

What happens if you try to access class private members and methods from outside the class?

Answer 29

Compile time error

Question 30

Observer/accessor and transformer/mutator methods otherwise known as?

Answer 30

Getters and setters

Question 31

Observer/accessor methods are declared with which keyword following parameter list?

Answer 31

Const

Question 32

Classes should be structured into header files which delineate the class I to its:

Answer 32

Implementation and specification

Question 33

Specification of a class?

Answer 33

Its public interface

Question 34

Implementation of a class?

Answer 34

Its internal workings

Question 35

What type of file is produced by a multi file project before the executable?

Answer 35

.obj files

Question 36

The individual data stored by objects, what it is?

Answer 36

Attributes

Question 37

Objects communicate in which way?

Answer 37

Message passing

Question 38

C way of referring to message passing?

Answer 38

Function application (of a public member function)

Question 39

What are responsibilities?

Answer 39

The public operations of a class provided for outside use

Question 40

What are the two types of responsibilities?

Answer 40

Action and knowledge

Question 41

Encapsulation?

Answer 41

The design of a class to privatise its internal state and member functions and provide a formal interface for interaction

Question 42

Formal interface?

Answer 42

Class’ documented specification

Question 43

Control abstraction?

Answer 43

Combining control statements into a single unit

Question 44

OOP paradigm lends itself to?

Answer 44

Modularity, modifiability, reuse

Question 45

Mutability and immutability with regards to objects?

Answer 45

Mutable objects can be altered after instantiation, immutable objects cannot

Question 46

Class declaration and implementation