Initialize method as constructor in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the initialize method in Ruby?

The initialize method is a special method in Ruby that acts as a constructor. It runs automatically when a new object is created, setting up initial values or state for that object.

beginner

How do you define an initialize method inside a Ruby class?

You define it like any other method but with the name <code>initialize</code>. It usually takes parameters to set up the object's initial state. Example:<br><pre>class Person
  def initialize(name)
    @name = name
  end
end</pre>

beginner

What does the @ symbol mean in @name = name inside initialize?

The @ symbol creates an instance variable. It stores data inside the object so it can be used later by other methods in the same object.

beginner

What happens if you create a new object without defining an initialize method?

Ruby uses a default constructor that does nothing. The object is created but no initial setup or variables are assigned automatically.

beginner

Can the initialize method take multiple parameters? How?

Yes, it can take as many parameters as needed, separated by commas. Example:<br>

def initialize(name, age)
  @name = name
  @age = age
end

What is the role of the initialize method in Ruby?

A It sets up initial values when an object is created

B It deletes an object

C It prints output to the screen

D It pauses the program

The initialize method runs automatically when a new object is created to set up initial values.

How do you call the initialize method directly?

A By calling <code>init()</code>

B By typing <code>initialize()</code>

C You never call it directly; Ruby calls it when you use <code>.new</code>

D By calling <code>constructor()</code>

Ruby automatically calls initialize when you create a new object with .new.

What does @name represent inside the initialize method?

A An instance variable that stores data for the object

B A local variable only inside the method

C A global variable

D A method name

@name is an instance variable that belongs to the object and keeps data accessible to other methods.

What happens if you define initialize with parameters but call .new without arguments?

A The program ignores the parameters

B Ruby uses default values automatically

C The object is created with nil values

D Ruby raises an error because arguments are missing

If parameters are required in initialize, you must provide them when calling .new, or Ruby raises an error.

Which keyword is used to create a new object that triggers initialize?

A .build

B .new

C .create

D .start

The .new method creates a new object and automatically calls initialize.

Explain how the initialize method works as a constructor in Ruby and why it is useful.

Think about what happens when you create a new object with .new.

Describe how you would define an initialize method that takes two parameters and stores them in instance variables.

Remember the format: def initialize(param1, param2)