Single Responsibility Principle in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Single Responsibility Principle (SRP)?

SRP means a class or module should have only one reason to change. It should do one job only.

beginner

Why is SRP important in system design?

It makes code easier to understand, test, and maintain. Changes in one part don't affect others.

beginner

Give a real-life example of SRP.

A car's steering system only controls direction. It doesn't handle engine or brakes. Each part has one job.

intermediate

What can happen if SRP is ignored?

Classes become complex and hard to fix. One change may break many things, causing bugs.

intermediate

How does SRP relate to maintainability?

With SRP, each part is simple and focused. This makes fixing and updating easier and safer.

What does the Single Responsibility Principle state?

A A class should be as large as possible

B A class should handle multiple responsibilities

C A class should have only one reason to change

D A class should never change

SRP means each class or module should have only one reason to change.

Which is a benefit of following SRP?

A Code is easier to maintain

B Changes in one part affect many others

C Code becomes harder to test

D Classes become more complex

SRP makes code easier to maintain by keeping responsibilities separate.

Ignoring SRP can lead to:

A Simpler code

B More bugs and complex classes

C Faster development always

D No impact on design

Ignoring SRP often causes complex classes and more bugs.

Which example best follows SRP?

A A class that manages user login and payment processing

B A class that changes for many reasons

C A class that does everything in the system

D A class that only handles user authentication

A class handling only user authentication follows SRP.

SRP helps in:

A Improving code maintainability

B Reducing code readability

C Making classes do many jobs

D Increasing coupling

SRP improves maintainability by keeping code focused.

Explain the Single Responsibility Principle and why it matters in system design.

Think about how one class should do only one job.

Describe a real-life analogy that helps understand SRP.

Consider parts of a car or kitchen tools.