SOLID principles in Software Engineering - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the 'S' in SOLID stand for?

It stands for <em>Single Responsibility Principle</em>. This means a class or module should have only one reason to change, focusing on a single task or responsibility.

beginner

Explain the Open/Closed Principle in simple terms.

It means software entities like classes should be open for extension but closed for modification. You can add new features without changing existing code.

intermediate

What is the Liskov Substitution Principle?

It says that objects of a parent class should be replaceable with objects of a child class without affecting the program's correctness.

intermediate

Describe the Interface Segregation Principle.

This principle advises that no client should be forced to depend on methods it does not use. It's better to have many small, specific interfaces than one large, general one.

advanced

What does the Dependency Inversion Principle promote?

It promotes that high-level modules should not depend on low-level modules. Both should depend on abstractions. Also, abstractions should not depend on details; details should depend on abstractions.

Which SOLID principle means a class should have only one reason to change?

A Single Responsibility Principle

B Open/Closed Principle

C Liskov Substitution Principle

D Dependency Inversion Principle

The Single Responsibility Principle states that a class should have only one reason to change.

What does the Open/Closed Principle encourage?

A Classes should be open for modification but closed for extension

B Classes should depend on concrete implementations

C Classes should have many responsibilities

D Classes should be open for extension but closed for modification

Open/Closed Principle means classes should be open for extension but closed for modification.

According to the Liskov Substitution Principle, a subclass should be able to replace its superclass without:

A Using interfaces

B Adding new methods

C Changing the program's correctness

D Changing variable names

Liskov Substitution Principle requires that subclasses can replace superclasses without affecting correctness.

The Interface Segregation Principle suggests:

A Use many small, specific interfaces

B Clients should depend on interfaces they do not use

C Use one large interface for all clients

D Avoid using interfaces

Interface Segregation Principle encourages many small, specific interfaces rather than one large one.

Dependency Inversion Principle states that:

A High-level modules depend on low-level modules

B Both depend on abstractions

C Low-level modules depend on high-level modules

D Abstractions depend on details

Dependency Inversion Principle says both high-level and low-level modules should depend on abstractions.

Explain each of the SOLID principles in your own words and give a simple example for one of them.

Think about how each principle helps keep code easy to maintain and extend.

Why are the SOLID principles important in software development? Describe how they help in real-life coding projects.

Consider how following these principles affects teamwork and code quality.