Master Software Design Patterns: Enhance Code Quality and Maintainability

Question 1

Which design pattern can be used to add new responsibilities to an object dynamically, even at runtime?

Accepted Answer

Decorator

Answer

Strategy

Answer

Observer

Answer

Mediator

Question 2

Which behavioural design pattern allows multiple objects to subscribe to and receive notifications from a central publisher object?

Accepted Answer

Observer

Answer

Command

Answer

Chain of Responsibility

Answer

Interpreter

Question 3

Which behavioural design pattern allows objects to communicate with each other through an intermediary?

Accepted Answer

Mediator

Answer

Observer

Answer

Command

Answer

Visitor

Question 4

What is a key benefit of using a builder design pattern?

Accepted Answer

Creating complex objects in a step-by-step manner

Answer

Ensuring immutability of the created object

Question 5

Which of the following is not a category of software design patterns?

Accepted Answer

Concurrency

Answer

Creational

Answer

Structural

Answer

Behavioural

Question 6

Which structural design pattern enables the composition of objects into tree structures to represent hierarchical relationships?

Accepted Answer

Composite

Answer

Adapter

Answer

Decorator

Answer

Proxy

Question 7

Which structural design pattern enables an object to have multiple representations, which are selected at runtime?

Accepted Answer

Decorator

Answer

Adapter

Answer

Composite

Answer

Proxy

Question 8

Which behavioural design pattern defines an object that wraps a command, allowing other objects to be parameterized?

Accepted Answer

Command

Answer

Strategy

Answer

Observer

Answer

Iterator

Question 9

Which design principle states that classes should be designed to allow for extension without requiring modification?

Accepted Answer

Open-closed principle

Answer

Liskov substitution principle

Answer

Dependency inversion principle

Answer

Interface segregation principle

Question 10

Which software quality attribute measures the system's ability to maintain performance under varying load or conditions?

Accepted Answer

Scalability

Answer

Reliability

Answer

Maintainability

Answer

Security

Question 11

Which software design tool is used to visualize the design of a system, including relationships between objects, classes, and components?

Accepted Answer

Unified Modeling Language (UML)

Answer

Flowchart

Answer

Class diagram

Answer

Entity relationship diagram

Question 12

Which behavioural design pattern allows you to change the behavior of an object at runtime?

Accepted Answer

Strategy

Answer

Adapter

Answer

Facade

Answer

Proxy

Question 13

Which structural design pattern provides a single point of access to a set of related objects?

Accepted Answer

Facade

Answer

Composite

Answer

Decorator

Answer

Proxy

Question 14

Which of the following is NOT a type of design pattern?

Accepted Answer

Data Manipulation

Answer

Creational

Answer

Structural

Answer

Behavioural

Question 15

Which creational design pattern is used to create objects that are only needed once?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Strategy

Answer

Composite

Question 16

Which structural design pattern allows you to add new functionality to an object without modifying the original object?

Accepted Answer

Decorator

Answer

Adapter

Answer

Facade

Answer

Proxy

Question 17

Which structural design pattern is used to represent a tree-like structure?

Accepted Answer

Composite

Answer

Strategy

Answer

Observer

Answer

Command

Question 18

Which behavioural design pattern is used to create a chain of objects where each object processes a request in turn?

Accepted Answer

Chain of Responsibility

Answer

Observer

Answer

Command

Answer

Strategy

Question 19

Which of the following is NOT considered a creational design pattern?

Accepted Answer

Adapter

Answer

Singleton

Answer

Factory Method

Answer

Builder

Question 20

Which structural design pattern is primarily used to connect two incompatible interfaces?

Accepted Answer

Adapter

Answer

Facade

Answer

Decorator

Answer

Composite

Question 21

What is the main objective of the Observer pattern?

Accepted Answer

To facilitate communication and updates between objects.

Answer

To provide a consistent way to create and manage objects.

Answer

To encapsulate complex code into reusable components.

Answer

To enable the sharing of data between remote objects.

Question 22

Which design pattern encapsulates a family of algorithms, allowing them to be interchangeable while maintaining consistency?

Accepted Answer

Strategy

Answer

Template Method

Answer

Composite

Answer

Decorator

Question 23

Who are commonly referred to as the "Gang of Four" in the context of design patterns?

Accepted Answer

A group of software engineers who popularized the concept of design patterns.

Answer

A set of design principles that guide the development of reusable code.

Answer

A type of software architecture that promotes modularity and flexibility.

Answer

A methodology for designing object-oriented systems.

Question 24

Which design pattern allows for adding additional functionality to an existing object without altering its interface?

Accepted Answer

Decorator

Answer

Observer

Answer

Builder

Answer

Template Method

Question 25

Which of the following design patterns does NOT belong to the creational pattern category?

Accepted Answer

Strategy

Answer

Factory Method

Answer

Singleton

Answer

Builder

Question 26

What is the primary goal of the Observer design pattern?

Accepted Answer

To define a one-to-many dependency between objects, where changes to one object are automatically reflected in the others

Answer

To provide a mechanism for creating objects without specifying the exact class to be instantiated

Answer

To define a family of related algorithms, allowing the algorithm to be selected at runtime

Answer

To provide a way to defer the creation of an object until it is needed

Question 27

Explain the key difference between a concrete factory and an abstract factory in design patterns.

Accepted Answer

A concrete factory produces specific, concrete products, while an abstract factory produces abstract products that define an interface for concrete products.

Answer

A concrete factory can create any type of product, while an abstract factory can only create products of a specific type.

Answer

There is no distinction between concrete factories and abstract factories; they serve the same purpose.

Answer

A concrete factory produces abstract products, while an abstract factory produces concrete products.

Question 28

Which of the following is not a creational design pattern?

Accepted Answer

Command

Answer

Factory Method

Answer

Builder

Answer

Singleton

Question 29

What is the purpose of the Adapter pattern?

Accepted Answer

Make incompatible classes work together

Answer

Create new objects without specifying the exact class

Answer

Provide a consistent interface to a group of related classes

Answer

Define a common interface for object interaction

Question 30

What is the responsibility of the Observer pattern?

Accepted Answer

Notify multiple objects about changes in a subject

Answer

Create a new object when needed

Answer

Define a common interface for creating families of related or dependent objects

Answer

Encapsulate a set of behaviour and make it available to other objects

Question 31

Which of the following is a good practice when naming design patterns?

Accepted Answer

Use descriptive and meaningful names

Answer

Use short and concise names

Answer

Use names that reflect the implementation details

Answer

Use names that are easy to remember

Question 32

What is the main purpose of the Singleton pattern?

Accepted Answer

Ensure that there is only one instance of a class

Answer

Create objects without specifying the exact class

Answer

Provide a consistent interface for a group of related classes

Answer

Encapsulate a set of behaviour and make it available to other objects

Question 33

In the Strategy pattern, what is the role of the Context object?

Accepted Answer

Calls the algorithm and passes it the necessary data

Answer

Contains the algorithm to be executed

Answer

Defines the interface for the algorithm

Answer

Stores the state of the algorithm

Question 34

What are the primary advantages of using design patterns in software development?

Accepted Answer

Improved code reusability, maintainability, and potentially reduced development time

Answer

Increased code complexity and reduced maintainability

Question 35

Which design pattern hides the specific class of objects that are created?

Accepted Answer

Factory Method

Answer

Builder

Answer

Singleton

Answer

Prototype

Question 36

Which structural pattern organises objects into a tree structure?

Accepted Answer

Composite

Answer

Adapter

Answer

Facade

Answer

Bridge

Question 37

Which behavioural pattern provides interchangeable implementations of an algorithm?

Accepted Answer

Strategy

Answer

Observer

Answer

Command

Answer

Iterator

Question 38

What is the main purpose of the Singleton design pattern?

Accepted Answer

To limit a class to a single instance

Answer

To encapsulate data and behaviour

Answer

To provide an alternative to inheritance

Answer

To create multiple instances of a class

Question 39

Which design pattern allows for dynamic addition of functionality without modifying the original class?

Accepted Answer

Decorator

Answer

Template Method

Answer

Adapter

Answer

Proxy

Question 40

What is the key distinction between the Factory Method and Abstract Factory design patterns?

Accepted Answer

The Abstract Factory creates families of related objects, while the Factory Method creates individual objects

Answer

The Factory Method is more flexible than the Abstract Factory

Question 41

Which behavioural pattern provides an intermediary object to control access to another object?

Accepted Answer

Proxy

Answer

Chain of Responsibility

Answer

Observer

Question 42

What is a primary advantage of using design patterns?

Accepted Answer

They offer proven solutions to common software development challenges

Answer

They make code more complex

Answer

They increase the risk of bugs

Answer

They eliminate the need for programmers to learn new techniques

Question 43

What is the fundamental principle of the Iterator design pattern?

Accepted Answer

Separating the iteration mechanism from the structure of the collection

Answer

Providing a consistent way to access elements

Answer

Encapsulating the implementation of an iteration

Answer

Traversing a collection in reverse order

Question 44

The _______ pattern ensures that a class has only one instance, providing a global point of access.

Accepted Answer

Singleton

Answer

Prototype

Answer

Factory Method

Answer

Facade

Question 45

Which structural pattern represents a tree-like structure where each node can have multiple child nodes?

Accepted Answer

Composite

Answer

Decorator

Answer

Adapter

Answer

Bridge

Question 46

The _______ pattern provides a simple interface to a complex subsystem, hiding the intricate details.

Accepted Answer

Facade

Answer

Flyweight

Answer

Mediator

Answer

Proxy

Question 47

What is the primary purpose of the Adapter pattern?

Accepted Answer

To make classes with incompatible interfaces compatible.

Answer

To create objects without specifying their concrete classes.

Answer

To ensure a class has only one instance.

Question 48

Which behavioural pattern allows an object to change its behaviour at runtime based on its internal state?

Accepted Answer

State

Answer

Template Method

Answer

Observer

Answer

Strategy

Question 49

The _______ pattern defines an algorithm's structure, leaving specific steps to its subclasses for implementation.

Accepted Answer

Template Method

Answer

Iterator

Answer

Chain of Responsibility

Answer

Command

Question 50

Which pattern defines a one-to-many dependency between objects, where changes in one object's state trigger notifications to its dependents?

Accepted Answer

Observer

Answer

Visitor

Answer

Mediator

Answer

Memento

Question 51

What is a key benefit of utilizing design patterns in software development?

Accepted Answer

Enhanced code reusability, maintainability, and communication

Answer

Reduced need for object-oriented programming principles

Answer

Elimination of all software errors

Question 52

Which pattern encapsulates a request as an object, enabling the customization of clients with varying requests?

Accepted Answer

Command

Answer

Interpreter

Answer

Chain of Responsibility

Answer

Strategy