IKM - International Knowledge Measurement Object-Oriented Programming Principles Questions and Answers

Question 1

A developer creates a `Vehicle` class and then defines `Car`, `Truck`, and `Motorcycle` classes that each derive from the `Vehicle` class.
Each of these new classes can now reuse the common methods and properties of the `Vehicle` class.
Which object-oriented principle does this scenario best exemplify?

Accepted Answer

Inheritance

Answer

Encapsulation

Answer

Polymorphism

Answer

Abstraction

Question 2

Which of the following best describes the principle of Encapsulation in object-oriented programming?

Accepted Answer

Bundling the data (attributes) and the methods (functions) that operate on the data into a single unit, or class, and restricting access to the internal state.

Answer

Exposing only the essential features of an object while hiding the complex implementation details.

Answer

Allowing an object to take on many forms or have multiple behaviors through a single interface.

Answer

Creating new classes from existing classes to establish a parent-child relationship and promote code reuse.

Question 3

A program uses a `Shape` class with a method called `draw()`. Several other classes, such as `Circle`, `Square`, and `Triangle`, inherit from `Shape` and provide their own specific implementation of the `draw()` method. When the program calls the `draw()` method on a list of `Shape` objects, the correct `draw()` implementation is executed for each specific shape. This is an example of:

Accepted Answer

Polymorphism

Answer

Composition

Answer

Data Hiding

Answer

Instantiation

Question 4

Consider a `DatabaseConnection` class. The user of this class only needs to know about methods like `connect()`, `query()`, and `disconnect()`. The complex internal details, such as managing network sockets, handling authentication protocols, and managing data buffers, are hidden from the user. Which OOP principle is most evident here?

Accepted Answer

Abstraction

Answer

Inheritance

Answer

Polymorphism

Answer

Encapsulation

Question 5

In object-oriented design, what is the primary purpose of defining a class with `private` attributes and `public` methods (getters and setters)?

Accepted Answer

To enforce encapsulation by controlling access to the object's internal state.

Answer

To ensure that all child classes can directly modify the attributes.

Answer

To allow any part of the program to access the attributes directly for efficiency.

Answer

To implement polymorphism through method overriding.

Question 6

Which statement accurately distinguishes Abstraction from Encapsulation?

Accepted Answer

Abstraction focuses on showing essential features (the 'what'), while Encapsulation is the mechanism of bundling data and hiding the implementation details (the 'how').

Answer

Abstraction is about bundling data and methods, while Encapsulation is about hiding implementation details.

Answer

Abstraction is a mechanism for code reuse through inheritance, while Encapsulation is for creating objects.

Answer

Encapsulation allows an object to behave differently in different contexts, while Abstraction provides a blueprint for objects.