Attr_reader, attr_writer, attr_accessor in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does attr_reader do in Ruby?

attr_reader creates a getter method for an instance variable. It lets you read the value but not change it directly.

beginner

What is the purpose of attr_writer in Ruby?

attr_writer creates a setter method for an instance variable. It lets you change the value but not read it directly.

beginner

Explain attr_accessor in Ruby.

attr_accessor creates both getter and setter methods for an instance variable. You can read and change the value.

intermediate

Why use attr_reader, attr_writer, or attr_accessor instead of writing methods manually?

They save time and make code cleaner by automatically creating simple getter and setter methods.

beginner

Given attr_reader :name, can you change the @name variable directly from outside the class?

No, attr_reader only allows reading the value. To change it, you need a setter method like attr_writer or attr_accessor.

Which Ruby attribute method allows both reading and writing an instance variable?

A attr_accessor

B attr_reader

C attr_writer

D attr_mutator

attr_accessor creates both getter and setter methods, allowing reading and writing.

What does attr_writer :age provide?

A A method to read @age

B A method to write @age

C Both read and write methods for @age

D No methods for @age

attr_writer creates a setter method to change the value of @age.

If a class has only attr_reader :title, what happens if you try to assign obj.title = 'New'?

A Raises an error

B It works fine

C Ignores the assignment

D Creates a new variable

Without a setter method, assigning to title raises a NoMethodError.

Which of these is NOT a reason to use attr_accessor?

A To reduce boilerplate code

B To automatically create getter and setter

C To make variables private

D To simplify class design

attr_accessor does not make variables private; it creates public getter and setter methods.

What is the default visibility of methods created by attr_reader, attr_writer, and attr_accessor?

A Module

B Protected

C Private

D Public

These methods are public by default, accessible from outside the class.

Describe the differences between attr_reader, attr_writer, and attr_accessor in Ruby.

Think about what each method lets you do with an instance variable.

Explain why using attr_accessor can make your Ruby class code cleaner and easier to maintain.

Consider how much code you save by not writing simple getter and setter methods.