Master Design Patterns: Enhance Your Software Design Skills

Question 1

Which of the following is a primary advantage of using design patterns in software engineering?

Accepted Answer

Simplified codebase and reduced complexity

Accepted Answer

Increased code maintainability and flexibility

Answer

Enhanced performance and efficiency

Answer

Reduced necessity for extensive testing

Question 2

Which design pattern is responsible for creating objects without specifying the exact class of the object to be created?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Prototype

Answer

Adapter

Question 3

Which design pattern is used to provide a surrogate or placeholder for another object to control access to it?

Accepted Answer

Proxy

Answer

Facade

Answer

Decorator

Answer

Composite

Question 4

Which design pattern defines an interface for creating a family of related objects without specifying their concrete classes?

Accepted Answer

Abstract Factory

Answer

Builder

Answer

Prototype

Answer

Singleton

Question 5

Which design pattern is used to convert the interface of a class into another interface clients expect?

Accepted Answer

Adapter

Answer

Facade

Answer

Proxy

Answer

Decorator

Question 6

Which design pattern is used to define a common interface for a set of classes, allowing objects to be composed dynamically?

Accepted Answer

Composite

Answer

Strategy

Answer

Adapter

Answer

Proxy

Question 7

Which design pattern is used to define a family of algorithms, encapsulate each one, and make them interchangeable?

Accepted Answer

Strategy

Answer

Command

Answer

Observer

Answer

Adapter

Question 8

Which design pattern ensures that only a single instance of a class can be created?

Accepted Answer

Singleton

Answer

Factory

Answer

Observer

Answer

Strategy

Question 9

The Factory pattern is primarily used to:

Accepted Answer

Create objects without specifying the exact class of the object.

Answer

Ensure that only one instance of a class is created.

Answer

Notify objects when a state change occurs.

Answer

Define a family of algorithms that are interchangeable.

Question 10

Which design pattern represents a one-to-many dependency between objects?

Accepted Answer

Observer

Answer

Mediator

Answer

Decorator

Answer

Builder

Question 11

The Strategy pattern allows you to:

Accepted Answer

Define a family of algorithms.

Answer

Encapsulate the creation of an object.

Answer

Control the access to an object.

Answer

Notify objects when a state change occurs.

Question 12

When is the Singleton pattern most appropriate to use?

Accepted Answer

When you need to control the creation and access to a single, global object.

Answer

When you need to create multiple instances of an object with different states.

Answer

When you need to notify objects when a state change occurs.

Answer

When you want to define a family of interchangeable algorithms.

Question 13

Which design pattern is categorized as a creational pattern?

Accepted Answer

Factory

Answer

Observer

Answer

Decorator

Answer

Adapter

Question 14

The Adapter pattern is used to:

Accepted Answer

Make unrelated classes work together.

Answer

Create objects without specifying the exact class of the object.

Answer

Notify objects when a state change occurs.

Answer

Define a family of interchangeable algorithms.

Question 15

Which design pattern provides a simplified interface to a complex system?

Accepted Answer

Facade

Answer

Decorator

Answer

Proxy

Answer

Mediator

Question 16

What is an advantage of using design patterns?

Accepted Answer

Reduced code complexity

Answer

Longer development time

Answer

Increased maintenance costs

Answer

More security flaws

Question 17

Which design pattern enables multiple objects to subscribe to and respond to events from a single object?

Accepted Answer

Observer

Answer

Decorator

Answer

Proxy

Answer

Composite

Question 18

Which design pattern allows an object to change its behavior based on its internal state changes?

Accepted Answer

State

Answer

Strategy

Answer

Template Method

Answer

Command

Question 19

Which design pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable, enabling algorithms to vary independently from their clients?

Accepted Answer

Strategy

Answer

Decorator

Answer

Factory

Answer

Adapter

Question 20

Which design pattern encapsulates the interaction between a set of objects, providing a simplified interface for users to interact with the system without understanding its internal structure?

Accepted Answer

Facade

Answer

Composite

Answer

Mediator

Answer

Bridge

Question 21

Which design pattern enables objects to be organized hierarchically and allows clients to treat individual objects and compositions of objects uniformly?

Accepted Answer

Composite

Answer

Decorator

Answer

Builder

Answer

Iterator

Question 22

Which design pattern provides an object representation of a hierarchy, allowing a user to interact with it without knowing its internal structure?

Accepted Answer

Composite

Answer

Adapter

Answer

Proxy

Answer

Command

Question 23

Which design pattern combines multiple objects into a single entity, providing a simpler interface for interacting with them collectively?

Accepted Answer

Facade

Answer

Decorator

Answer

Bridge

Answer

Proxy

Question 24

What is the primary purpose of the Singleton pattern?

Accepted Answer

To ensure that only one instance of a class exists

Answer

To create multiple instances of a class

Answer

To manage the state of an object

Answer

To provide an interface for creating objects

Question 25

What is the key distinction between a concrete class and an abstract class?

Accepted Answer

A concrete class can be instantiated, while an abstract class cannot

Answer

An abstract class can be instantiated, while a concrete class cannot

Answer

They both can be instantiated

Answer

They both cannot be instantiated

Question 26

In the context of the Observer pattern, what is the primary role of an observer?

Accepted Answer

To receive notifications from a subject

Answer

To notify other objects of changes

Answer

To manage the state of a subject

Answer

To create new subjects

Question 27

Which design pattern defines an interface for creating objects, but allows subclasses to alter the created object's type?

Accepted Answer

Factory Method

Answer

Singleton

Answer

Prototype

Answer

Builder

Question 28

Which popular design pattern guarantees that there is exactly one instance of a class and provides a global access point to that instance?

Accepted Answer

Singleton

Answer

Factory Method

Answer

Observer

Answer

Bridge

Question 29

Which design pattern models a one-to-many dependency between objects, where changes to one object automatically propagate to its dependents?

Accepted Answer

Observer

Answer

Strategy

Answer

Iterator

Answer

Adapter

Question 30

Which design pattern enables the behavior of an object to be modified dynamically by replacing its associated strategy object?

Accepted Answer

Strategy

Answer

Chain of Responsibility

Answer

Facade

Answer

Bridge

Question 31

Which design pattern conceals the complexity of a subsystem by providing a simplified interface, thereby making the subsystem easier to use?

Accepted Answer

Facade

Answer

Bridge

Answer

Adapter

Answer

Decorator

Question 32

Which design pattern is commonly used for event handling and asynchronous programming, where objects can subscribe to events and receive notifications when those events occur?

Accepted Answer

Observer

Answer

Strategy

Answer

Iterator

Answer

Facade

Question 33

Which design pattern establishes a one-to-many dependency between objects, where changes to the state of one object automatically propagate updates to all dependent objects?

Accepted Answer

Observer

Answer

Composite

Answer

Mediator

Answer

Strategy

Question 34

Which design pattern ensures that a class has only one instance?

Accepted Answer

Singleton

Answer

Factory

Answer

Bridge

Answer

Command

Question 35

Which design pattern provides an interface for creating objects but allows subclasses to alter the type of objects that will be created?

Accepted Answer

Factory Method

Answer

Iterator

Answer

Adapter

Answer

Builder

Question 36

Which design pattern describes a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically?

Accepted Answer

Observer

Answer

Decorator

Answer

Strategy

Answer

Facade

Question 37

Which design pattern allows objects to be wrapped with additional responsibilities without changing their class?

Accepted Answer

Decorator

Answer

Composite

Answer

Proxy

Answer

Template Method

Question 38

Which design pattern is primarily used to simplify the design of a complex system by breaking it down into smaller, more manageable components?

Accepted Answer

Facade

Answer

Iterator

Answer

Decorator

Answer

Strategy

Question 39

Which design pattern allows objects to vary independently from the clients that use them?

Accepted Answer

Strategy

Answer

Visitor

Answer

Observer

Answer

Adapter

Question 40

Which design pattern provides a way to traverse elements of an aggregate object sequentially without exposing the underlying representation?

Accepted Answer

Iterator

Answer

Composite

Answer

Observer

Answer

Decorator

Question 41

Which design pattern is used to create a new object by copying an existing object, while providing the ability to modify the cloned object?

Accepted Answer

Prototype

Answer

Observer

Answer

Singleton

Answer

Builder

Question 42

Which design pattern guarantees that a class has only one instance throughout the application?

Accepted Answer

Singleton

Answer

Facade

Answer

Observer

Answer

Builder

Question 43

Which design pattern is employed to instantiate objects without explicitly specifying the exact class?

Accepted Answer

Factory

Answer

Strategy

Answer

Builder

Answer

Decorator

Question 44

Which design pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable?

Accepted Answer

Strategy

Answer

Facade

Answer

Singleton

Answer

Builder

Question 45

Which design pattern constructs complex objects step by step, without specifying their internal representation?

Accepted Answer

Builder

Answer

Prototype

Answer

Observer

Answer

Factory

Question 46

Which design pattern provides a simplified interface to a complex subsystem or set of classes?

Accepted Answer

Facade

Answer

Observer

Answer

Adapter

Answer

Composite

Question 47

Which design pattern passes requests along a chain of objects until one handles it or all fail?

Accepted Answer

Chain of Responsibility

Answer

Observer

Answer

Decorator

Answer

Command

Question 48

Which design pattern represents a request as an object, allowing for parametrization, queuing, logging, or undoing?

Accepted Answer

Command

Answer

Builder

Answer

State

Answer

Memento