CodeSignal Technical Assessment Object-Oriented Programming 3

Question 1

What does the Liskov Substitution Principle (LSP) require?

Accepted Answer

Objects of a superclass should be replaceable with objects of its subclasses without breaking program correctness

Answer

A class should have only one reason to change

Answer

High-level modules should not depend directly on low-level modules

Answer

Interfaces should be client-specific rather than general-purpose

Question 2

What is a design pattern in object-oriented software development?

Accepted Answer

A reusable solution template for commonly recurring problems in software design

Answer

A concrete algorithm guaranteed to solve a specific computational problem optimally

Answer

The visual notation used to draw class diagrams in UML

Answer

A mandatory code structure enforced by the OOP language compiler

Question 3

Which design pattern ensures that only one instance of a class is ever created and provides a global access point to it?

Accepted Answer

Singleton

Answer

Factory

Answer

Observer

Answer

Decorator

Question 4

What problem does the Factory design pattern solve?

Accepted Answer

Decoupling object creation from the code that uses the object by delegating instantiation to a factory

Answer

Dynamically adding behavior to objects without modifying their class

Answer

Converting an incompatible interface into one a client expects

Answer

Notifying multiple objects automatically when another object's state changes

Question 5

What does the Observer design pattern define?

Accepted Answer

A one-to-many dependency so that when one object changes state all dependents are automatically notified

Answer

A pattern where one object acts as a transparent proxy for another

Answer

A pattern that allows an object to appear to change its class when its internal state changes

Answer

A pattern that encapsulates an algorithm inside an object so it can be swapped at runtime

Question 6

What does 'tight coupling' mean in OOP design?

Accepted Answer

Classes are highly dependent on each other's concrete implementations, making change difficult

Answer

Classes are well-structured and adhere strictly to SOLID principles

Answer

Multiple classes all inherit from the same common parent class

Answer

All class members are marked private to enforce strong encapsulation

Question 7

What is the primary purpose of the Decorator design pattern?

Accepted Answer

To add new behaviors to an object dynamically at runtime without altering its class definition

Answer

To guarantee only one instance of a class exists at any time

Answer

To provide a single simplified interface to a complex subsystem of classes

Answer

To convert the interface of one class into an interface expected by a client