Object Oriented Programming

Question 1

Derived Classes/Child Classes

Answer 1

An EXTENSION of a base class Classes that inherit functions and variables from a base class
aka “child” class

Question 2

Base class/Parent Class

Answer 2

Class that can be EXTENDED by a derived class.
Includes functions and variables that can be inherited by a derived class

Question 3

Inheritance

Answer 3

Mechanism for EXTENDING a class
-If you extend the class rather than editing it, you will not have to “re-debug” the original code (because it was not changed since the last time you debugged)
-It allows you to reuse existing DEBUGGED code by allowing a class to acquire properties (data and operations) of another class

Question 4

Multiple Inheritance

Answer 4

Inheritance of properties from multiple classes
-Generally not recommended, but some languages (like C++) will allow it

Question 5

“Public”

Answer 5

Indicates that the data/operation can interface with the rest of the world
can be accessed from outside of the class

Question 6

“Private”

Answer 6

Indicates that the data/operation can only interface with member functions of the class in which it was written

Question 7

“Protected”

Answer 7

Indicates that the data/operation can ONLY interface with the data/operations of a derived class
DO NOT USE THIS UNLESS YOU KNOW THE CLASS IS GOING TO BE INHERITED (otherwise you can get yourself in trouble when it comes to debugging)

Question 8

Practical applications of inheritance

Answer 8

1. Principle of Least Privilege & Role-based access control
   The most general base class should have the fewest permissions. As the roles become more specific, they are given more and more privileges.
   2.

Question 9

Reading a class block in a class diagram

Answer 9

Minus (-) inidicates private.
Plus (+) indicates public.
Pound sign (#) indicates “protected”.
The name of the class goes in the top box.
The data/variables of the class go in the middle box.
The operations/functions of the class go in the bottom box.

Question 10

Inheriting “private” variables/function

Answer 10

Private members of the Base Class are present within objects of the Derived Class but are NOT directly accessible within the Derived Class code

Question 11

Constructors

Answer 11

Constructors are not inherited.

Question 12

Representing a derived class in a UML class diagram

Answer 12

Only show what is EXCLUSIVE to the derived class.
NEW variables
NEW functions
Anything that is overwritten

Question 13

Memory handling of inheritance

Answer 13

When you create a child class, you are also “creating” a parent class inside of that child class. There is a Base class object nested within each Derived class object. The base class object literally comes directly before the derived class in memory. The Base class object “contains” all inherited members

Question 14

Accessing private members of the base class

Answer 14

If the derived class inherits PUBLIC functions from the base class…. then those functions can still access the private variables of the base class via that public function it just inherited

Question 15

Constructor inheritance

Answer 15

No such thing. Derived classes do not inherit the constructor from the base class.
You will have to make a new constructor for the derived class.

Question 16

Order in which the destructors are called

Answer 16

Destructors are called in the upward inheritance order (less abstract constructors come first) Derived class destructors will be called before the base class destructor.

Question 17

Parameters

Answer 17

Parameters are needed in the function header. It is a DECLARATION of variables that you can expect to find in that function. They require datatypes just like any declaration

Question 18

Order in which the constructors are called

Answer 18

Constructors are called in the downward inheritance order (more abstract constructors come first) Base class constructors are called before the derived class constructors.

Question 19

Arguments

Answer 19

Arguments are needed when the function is CALLED. They represent actual variable names so that you can pass actual values to the function. They do not require datatypes

Question 20

Calling a function from the based class inside a function of the same name within the derived class

Answer 20

This is completely legal. But it you must specify the location of the function you are calling (in C++ this is done using:
base_name::function_name

Question 21

What is the purpose/role of the constructor?

Answer 21

lol

Question 22

What is the purpose/role of the destructor?

Answer 22

lol

Question 23

What is the sequence of steps the machine goes through when it executes a program that includes both a base class AND a derived class that extends that base class?

Question 24

Purpose of the #ifndef guard?

Answer 24

You NEED it to keep the code from redundant imports. You do not want to import the same file more than once and if you use multiple sourcecode files, it is extremely likely that you have importanted something more than once because some files (like iostream string.h) are included in almost every C++ program

Question 25

Static Binding

Answer 25

Mean that something is decided how it behaves when you WRITE the code.
Compile-time determination of which function to call for a particular object

Question 26

Dynamic Binding

Answer 26

Means that something is decided how it behaves when you EXECUTE the code.
Run-time determination of which function to call for a particular object

Question 27

Polymorphism

Answer 27

The ability to determine which of several operations with the same name is appropriate

Question 28

Polymorphic Operation

Answer 28

An Operation that has multiple meanings depending upon the data type of the object to which it is bound at run time

Question 29

Abstract Data Type

Answer 29

Data type whose properties (domain and operations) are specified independently of any implementation

Question 30

Class

Answer 30

–A structured type used to model abstract data types
–Encapsulate attributes (data) with the member functions that modify
the attribute values

Question 31

Object

Answer 31

–An instance of a class
–Set of attribute values define the state of an object at a given time
–Member functions and attributes accessed using the member
selection operator (period .)

Question 32

Client

Answer 32

–Software that declares and manipulates objects of a particular class
type

Question 33

public members of a class

Answer 33

Can be accessed from outside of the class

Question 34

private members of a class

Answer 34

Accessible only by the code within the implementation file and is not accessible by
code outside of the class
- Client cannot interact directly with private
variables or functions within object

Question 35

Specification file

Answer 35

*The declaration of the class type
*Include guards (more on this later)

Question 36

Implementation File

Answer 36

*Code that implements the member functions of the class

Question 37

Unit Testing

Answer 37

• Performed with a
  dedicated driver program
  –Contains a simplified main function that creates instances
  of the class (objects) and then tests the objects by using its
  public interface
  –Multiple source files must be compiled and linked to create
  the executable
  –Once tested, the class may be reused with the actual
  application program

Question 38

struct v. class

Answer 38

–A struct is a class whose members are public by default
–By default, all members of a C++ class are private
–Two built-in operations for structs and classes “.” and “=”

Question 39

Five categories of member functions

Answer 39

1. Constructors
2. Transformers
3. Observers
4. Iterators
5. Destructors

Question 40

Constructor functions in a C++ class

Answer 40

Create and Initialize Object
Constructor methods have the same name as the class

Question 41

Transformers functions in a C++ class

Answer 41

Alter the state of an object

Question 42

Observer functions in a C++ class

Answer 42

Allow one to view the state of an object

Question 43

Iterator functions in a C++ class

Answer 43

Allow us to process (one at a time) all components of an ADT

Question 44

“const” for member functions

Answer 44

Member functions applied to an object may alter attributes stored within that object unless the reserved word const is used to prevent modification

Question 45

“self” for member functions

Answer 45

The object to which a member function
is applied