DRY (Don't Repeat Yourself) in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does DRY stand for in software design?

DRY stands for "Don't Repeat Yourself". It means avoiding duplication of code or logic to make systems easier to maintain and less error-prone.

beginner

Why is following the DRY principle important in system design?

Following DRY helps reduce bugs, makes code easier to update, and improves clarity by having a single source of truth for any piece of logic or data.

beginner

Give a real-life example that explains the DRY principle.

Imagine writing a recipe once and sharing it with friends instead of writing the same recipe multiple times. If you want to change the recipe, you only update it once, and everyone gets the update.

intermediate

How can DRY be applied in low-level design (LLD)?

In LLD, DRY can be applied by creating reusable functions, classes, or modules that handle common tasks instead of repeating similar code in multiple places.

intermediate

What problems can occur if DRY is not followed?

If DRY is ignored, code duplication can cause inconsistent behavior, harder maintenance, more bugs, and wasted effort when updating multiple copies of the same logic.

What is the main goal of the DRY principle?

A Make code longer for clarity

B Write code as fast as possible

C Use many different programming languages

D Avoid repeating code or logic

DRY means "Don't Repeat Yourself", so the main goal is to avoid repeating code or logic.

Which of these is a benefit of following DRY?

A More bugs due to repeated code

B More complex code structure

C Easier maintenance and updates

D Slower system performance

DRY reduces duplication, making maintenance and updates easier.

In low-level design, how can DRY be implemented?

A By copying code blocks multiple times

B By creating reusable functions or classes

C By writing everything in one big function

D By avoiding comments

Reusable functions or classes help avoid code repetition, following DRY.

What can happen if you do NOT follow DRY?

A Inconsistent behavior and more bugs

B You save time updating code

C Code becomes easier to maintain

D Code runs faster

Ignoring DRY leads to duplicated code, causing inconsistent behavior and more bugs.

Which analogy best explains DRY?

A Writing the same recipe once and sharing it

B Writing different recipes for every meal

C Copying recipes by hand multiple times

D Throwing away old recipes

Sharing one recipe instead of rewriting it multiple times illustrates DRY.

Explain the DRY principle and why it is important in system design.

Think about how repeating code can cause problems.

Describe how you would apply the DRY principle when designing a system at a low level.

Consider how to organize code to avoid copying the same logic.