Why SOLID principles guide maintainable design in LLD - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Single Responsibility Principle (SRP)

Which option best describes the Single Responsibility Principle in system design?

A A class should inherit from multiple classes to reuse code efficiently.

B A class should depend on concrete implementations rather than abstractions.

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

D A class should handle all related functionalities to reduce the number of classes.

💡 Hint

Think about how many reasons a class should have to change.

The Single Responsibility Principle states that a class should have only one reason to change, which means it should focus on a single responsibility to keep the design simple and maintainable.

❓ Architecture

intermediate

Applying Open/Closed Principle (OCP) in Design

Which design approach best follows the Open/Closed Principle to allow system extension without modification?

A Duplicate existing code to add new features quickly.

B Modify existing classes directly whenever new features are needed.

C Avoid using abstractions and rely on concrete classes only.

D Use inheritance or interfaces to add new behaviors by extending existing classes without changing them.

💡 Hint

Think about how to add new features without changing existing code.

The Open/Closed Principle encourages designs where classes are open for extension but closed for modification, often achieved by using inheritance or interfaces.

❓ scaling

advanced

Scaling with Dependency Inversion Principle (DIP)

How does applying the Dependency Inversion Principle help in scaling a software system?

A By making both high-level and low-level modules depend on abstractions, reducing tight coupling and improving flexibility.

B By making high-level modules depend on low-level modules directly for faster execution.

C By removing abstractions to simplify the codebase.

D By tightly coupling modules to reduce the number of interfaces.

💡 Hint

Consider how dependencies affect flexibility and change management.

Dependency Inversion Principle states that high-level modules should not depend on low-level modules directly; both should depend on abstractions, which helps in scaling by making the system more flexible and easier to change.

❓ tradeoff

advanced

Tradeoffs of Interface Segregation Principle (ISP)

What is a common tradeoff when applying the Interface Segregation Principle in system design?

A Ignoring interfaces altogether simplifies the design.

B Creating many small interfaces can increase complexity but improves client-specific design.

C Using one large interface reduces complexity and improves flexibility.

D Forcing clients to implement unused methods reduces code clarity.

💡 Hint

Think about the balance between interface size and client needs.

Interface Segregation Principle encourages creating smaller, client-specific interfaces to avoid forcing clients to depend on methods they do not use, but this can lead to more interfaces to manage.

❓ component

expert

Identifying SOLID Violations in a Component Design

Given a component that handles user authentication, logging, and data validation all in one class, which SOLID principle is most violated?

A Single Responsibility Principle, because the class has multiple reasons to change.

B Liskov Substitution Principle, because subclasses cannot replace the parent class.

C Dependency Inversion Principle, because the class depends on abstractions.

D Open/Closed Principle, because the class is open for extension.

💡 Hint

Think about how many jobs the class is doing.

A class handling multiple unrelated responsibilities violates the Single Responsibility Principle, making it harder to maintain and modify.