Why class-level behavior matters in Ruby - Quick Recap

Recall & Review

beginner

What is class-level behavior in Ruby?

Class-level behavior refers to methods and variables that belong to the class itself, not to individual objects created from the class.

beginner

Why is class-level behavior important in Ruby?

It allows sharing data and methods across all instances, helps organize code, and controls how objects are created or managed.

beginner

How do you define a class method in Ruby?

You define a class method by prefixing the method name with <code>self.</code> inside the class, like <code>def self.method_name</code>.

beginner

What is a real-life example of class-level behavior?

Think of a factory (class) that keeps track of how many products (objects) it has made. The count is stored at the class level, not in each product.

intermediate

What happens if you put data in instance variables instead of class variables for shared info?

Each object gets its own copy, so data is not shared. This can cause inconsistent or duplicated information.

In Ruby, how do you call a class method named info on class Car?

A Car#info

B Car.info

C car.info

D info.Car

Class methods are called on the class itself using dot notation, like Car.info.

Which keyword is used to define a class method inside a Ruby class?

A self

B class

C defclass

D static

Class methods are defined by prefixing the method name with self. inside the class.

What is the main benefit of using class-level variables in Ruby?

A Hiding data from the class

B Making each object unique

C Preventing method calls

D Sharing data among all instances

Class-level variables store data shared by all instances of the class.

If you want to count how many objects of a class have been created, where should you store the count?

A In a class variable

B In an instance variable

C In a local variable

D In a method parameter

A class variable keeps track of data shared by all objects, like a count of created instances.

What happens if you define a method without self. inside a Ruby class?

A It causes an error

B It becomes a class method

C It becomes an instance method

D It becomes a global method

Methods without self. are instance methods, called on objects, not the class.

Explain why class-level behavior matters when designing Ruby programs.

Think about how many objects share the same information.

Describe how to create and use a class method in Ruby with a simple example.

Remember class methods belong to the class, not objects.