Design Patterns and Principles

Question 1

What are Software Design Principles?

Answer 1

Software design principles are guidelines that help developers create scalable, maintainable, and efficient software systems. They help ensure that the software is structured well and can easily adapt to future changes.

Question 2

What are the key Software Design Principles?

Answer 2

1. SOLID Principles 2. DRY (Don’t Repeat Yourself) 3. KISS (Keep It Simple, Stupid) 4. YAGNI (You Aren’t Gonna Need It) 5. Separation of Concerns 6. Composition Over Inheritance

Question 3

What is the SOLID principle?

Answer 3

SOLID is an acronym representing five design principles that improve software design and development:
1. Single Responsibility Principle (SRP)
2. Open/Closed Principle (OCP)
3. Liskov Substitution Principle (LSP)
4. Interface Segregation Principle (ISP)
5. Dependency Inversion Principle (DIP)

Question 4

What is the Single Responsibility Principle (SRP)?

Answer 4

A class should have only one reason to change, meaning it should only have one responsibility or job.

Question 5

What is the Open/Closed Principle (OCP)?

Answer 5

Software entities (classes, modules, functions) should be open for extension but closed for modification, meaning that new functionality should be added without altering existing code.

Question 6

What is the Liskov Substitution Principle (LSP)?

Answer 6

Objects of a superclass should be replaceable with objects of a subclass without affecting the functionality of the system.

Question 7

What is the Interface Segregation Principle (ISP)?

Answer 7

Clients should not be forced to depend on interfaces they do not use, promoting the design of small, specific interfaces rather than large, general ones.

Question 8

What is the Dependency Inversion Principle (DIP)?

Answer 8

High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions.

Question 9

What is DRY (Don’t Repeat Yourself)?

Answer 9

The DRY principle emphasizes avoiding code duplication by creating reusable functions or modules, improving maintainability and reducing errors.

Question 10

What is KISS (Keep It Simple, Stupid)?

Answer 10

The KISS principle promotes simplicity in design and implementation, suggesting that systems should be designed in the simplest way possible without unnecessary complexity.

Question 11

What is YAGNI (You Aren’t Gonna Need It)?

Answer 11

The YAGNI principle advises developers to focus only on what is necessary for the current iteration and avoid adding functionality that may not be needed in the future.

Question 12

What is Separation of Concerns?

Answer 12

The principle of separating a software system into distinct sections, each responsible for a specific aspect of functionality, making the system easier to maintain and scale.

Question 13

What is Composition Over Inheritance?

Answer 13

Composition over inheritance is the design principle that encourages using object composition (creating classes with objects of other classes) rather than relying on class inheritance for extending functionality.

Question 14

What are Design Patterns?

Answer 14

Design patterns are reusable solutions to common software design problems. They are proven, best-practice solutions that can be applied to specific design challenges.

Question 15

What are the types of Design Patterns?

Answer 15

1. Creational Patterns 2. Structural Patterns 3. Behavioral Patterns

Question 16

What are Creational Design Patterns?

Answer 16

Creational design patterns deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. Examples include Singleton, Factory Method, and Abstract Factory.

Question 17

What is the Singleton Pattern?

Answer 17

The Singleton pattern ensures that a class has only one instance and provides a global point of access to that instance.

Question 18

What is the Factory Method Pattern?

Answer 18

The Factory Method pattern defines an interface for creating objects, but lets subclasses alter the type of objects that will be created.

Question 19

What is the Abstract Factory Pattern?

Answer 19

The Abstract Factory pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Question 20

What are Structural Design Patterns?

Answer 20

Structural design patterns focus on how to compose classes and objects to form larger structures while keeping the system flexible and efficient. Examples include Adapter, Composite, and Decorator patterns.

Question 21

What is the Adapter Pattern?

Answer 21

The Adapter pattern allows incompatible interfaces to work together by wrapping one interface with another that is compatible with the target system.

Question 22

What is the Composite Pattern?

Answer 22

The Composite pattern allows you to compose objects into tree-like structures to represent part-whole hierarchies, making it easier to treat individual objects and compositions uniformly.

Question 23

What is the Decorator Pattern?

Answer 23

The Decorator pattern allows behavior to be added to individual objects, dynamically, without affecting the behavior of other objects from the same class.

Question 24

What are Behavioral Design Patterns?

Answer 24

Behavioral design patterns deal with how objects interact and communicate with each other. Examples include Observer, Strategy, and Command patterns.

Question 25

What is the Observer Pattern?

Answer 25

The Observer pattern defines a one-to-many dependency, where a change in one object (the subject) triggers updates in all dependent objects (observers).

Question 26

What is the Strategy Pattern?

Answer 26

The Strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable, allowing the algorithm to be selected at runtime.

Question 27

What is the Command Pattern?

Answer 27

The Command pattern turns a request into a stand-alone object that contains all information about the request, allowing parameterization and queuing of requests.

Question 28

Why are Design Patterns important?

Answer 28

Design patterns provide reusable solutions to common software problems, making code easier to understand, maintain, and extend. They also encourage best practices and improve communication among developers.

Question 29

What are the advantages of using Design Patterns?

Answer 29

1. Reusability of proven solutions. 2. Improves code readability and maintainability. 3. Helps to solve common design issues efficiently. 4. Promotes consistency across software projects.

Question 30

What are the disadvantages of using Design Patterns?

Answer 30

1. May add complexity if used incorrectly. 2. Can result in over-engineering. 3. May not always be applicable to specific project needs.

Question 31

What is the list of Software Design Principles and Design Patterns?

Answer 31

Software Design Principles: 1. SOLID Principles 2. DRY (Don't Repeat Yourself) 3. KISS (Keep It Simple, Stupid) 4. YAGNI (You Aren't Gonna Need It) 5. Separation of Concerns 6. Composition Over Inheritance. Design Patterns: 1. Creational Patterns 2. Structural Patterns 3. Behavioral Patterns.