Protected and private visibility in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does private visibility mean in Ruby?

Methods marked as private can only be called within the same object. They cannot be called with an explicit receiver, even if it's self.

intermediate

What is the difference between protected and private methods in Ruby?

<strong>Protected</strong> methods can be called by any instance of the defining class or its subclasses, but only within the same family of objects. <strong>Private</strong> methods can only be called without an explicit receiver inside the same object.

beginner

How do you declare a method as private in Ruby?

You can declare a method as private by placing it below the keyword private in the class, or by calling private :method_name.

intermediate

Can a <strong>protected</strong> method be called from outside the class in Ruby?

No, <strong>protected</strong> methods cannot be called from outside the class or its subclasses unless the call is made between instances of the same class or subclass.

intermediate

Why use protected methods instead of private methods?

Use <strong>protected</strong> when you want to allow access to methods between instances of the same class or subclasses, but keep them hidden from outside objects. <strong>Private</strong> is stricter and only allows calls within the same object.

Which of the following is true about private methods in Ruby?

A They can be called from subclasses with an explicit receiver.

B They can be called from any object of the same class.

C They can be called only without an explicit receiver inside the same object.

D They can be called from outside the class with an explicit receiver.

Private methods in Ruby can only be called without an explicit receiver inside the same object.

What keyword do you use to declare protected methods in Ruby?

A private

B internal

C public

D protected

The keyword protected is used to declare protected methods in Ruby.

Can a protected method be called by another instance of the same class?

A Yes, protected methods can be called by other instances of the same class.

B No, protected methods can only be called within the same instance.

C No, protected methods are only accessible outside the class.

D Yes, but only if called with an explicit receiver from outside the class.

Protected methods allow access between instances of the same class or subclasses.

Which visibility level is the most restrictive in Ruby?

A protected

B private

C public

D internal

Private methods are the most restrictive because they cannot be called with an explicit receiver, even within the same class.

If you want a method to be accessible only within the same object, which visibility should you use?

A private

B protected

C public

D global

Private methods are accessible only within the same object without an explicit receiver.

Explain the difference between protected and private visibility in Ruby with an example.

Think about who can call the methods and from where.

Describe a real-life situation where using protected methods would be better than private methods.

Consider a family or team where members share some secrets but keep others private.