Dependency Inversion Principle in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Dependency Inversion Principle (DIP)?

DIP is a design principle that says high-level modules should not depend on low-level modules. Both should depend on abstractions. It helps make systems flexible and easier to change.

beginner

Why do we use abstractions in DIP?

Abstractions hide details and allow different parts of a system to work together without knowing the inner workings of each other. This reduces tight coupling and makes the system easier to maintain.

intermediate

In DIP, which direction should dependencies point?

Dependencies should point toward abstractions, not concrete implementations. This means high-level modules depend on interfaces or abstract classes, not on low-level module details.

intermediate

How does DIP improve system scalability?

By depending on abstractions, you can change or add new low-level modules without changing high-level modules. This makes it easier to add features or scale parts of the system independently.

beginner

Give a real-life example of Dependency Inversion Principle.

Think of a TV remote (high-level) and the TV (low-level). The remote depends on a standard interface (buttons) to control the TV, not on the TV's internal parts. This lets you use different remotes with different TVs easily.

What does the Dependency Inversion Principle promote?

A High-level modules depend on abstractions

B Low-level modules depend on high-level modules

C Modules depend on concrete implementations

D No dependencies between modules

DIP states that high-level modules should depend on abstractions, not on low-level modules.

Which of the following is an example of an abstraction in DIP?

A Database schema

B Concrete class implementation

C Interface or abstract class

D User interface layout

Abstractions are interfaces or abstract classes that hide implementation details.

How does DIP affect system maintenance?

A Makes maintenance harder due to tight coupling

B Improves maintenance by reducing dependencies on concrete code

C Has no effect on maintenance

D Requires rewriting all code frequently

DIP reduces tight coupling, making maintenance easier.

Which statement is true about dependencies in DIP?

A Dependencies point toward abstractions

B Dependencies point from low-level to high-level modules

C Dependencies point from high-level to low-level modules

D Dependencies are removed completely

In DIP, dependencies point toward abstractions, not concrete modules.

What is a benefit of following DIP in system design?

A System becomes rigid and hard to change

B System becomes tightly coupled

C System requires more code duplication

D System becomes flexible and easier to extend

DIP makes systems flexible and easier to extend by using abstractions.

Explain the Dependency Inversion Principle and why it is important in system design.

Think about how modules should connect through interfaces rather than direct code.

Describe a simple real-life analogy that illustrates the Dependency Inversion Principle.

Consider everyday devices like remotes, plugs, or adapters.