Why single inheritance in Ruby - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a class that inherits from another class in Ruby.

Ruby

class ChildClass < [1]
  def greet
    puts 'Hello from child'
  end
end

Drag options to blanks, or click blank then click option'

AParentClass

BChildClass

CObject

DModule

Attempts:

3 left

💡 Hint

Common Mistakes

Using the child class name instead of the parent class name after <.

Trying to inherit from a module using <.

The < symbol is used in Ruby to indicate inheritance. Here, ChildClass inherits from ParentClass.

2fill in blank

medium

Complete the code to call the parent class method from the child class in Ruby.

Ruby

class Parent
  def greet
    puts 'Hello from parent'
  end
end

class Child < Parent
  def greet
    [1]
    puts 'Hello from child'
  end
end

Drag options to blanks, or click blank then click option'

Asuper.greet

Bself.greet

CParent.greet

Dsuper

Attempts:

3 left

💡 Hint

Common Mistakes

Calling Parent.greet directly, which is incorrect syntax.

Using self.greet which causes infinite recursion.

In Ruby, super calls the same method from the parent class. Here, it calls greet from Parent.

3fill in blank

hard

Fix the error in the code to correctly inherit and override a method in Ruby.

Ruby

class Animal
  def speak
    puts 'Animal sound'
  end
end

class Dog [1] Animal
  def speak
    puts 'Bark'
  end
end

Drag options to blanks, or click blank then click option'

A>

B<

C=

Dinherits

Attempts:

3 left

💡 Hint

Common Mistakes

Using > or = instead of < for inheritance.

Writing 'inherits' as a keyword, which Ruby does not support.

In Ruby, the < symbol is used to indicate inheritance from a parent class.

4fill in blank

hard

Fill both blanks to create a class that inherits from a parent and calls the parent's method in Ruby.

Ruby

class Vehicle
  def start
    puts 'Vehicle started'
  end
end

class Car [1] Vehicle
  def start
    [2]
    puts 'Car started'
  end
end

Drag options to blanks, or click blank then click option'

A<

Bsuper

Cself

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using > instead of < for inheritance.

Using self instead of super to call the parent method.

The class Car inherits from Vehicle using <. Inside start, super calls the parent's start method.

5fill in blank

hard

Fill all three blanks to define a parent class, a child class inheriting it, and call the parent's method in Ruby.

Ruby

class [1]
  def info
    puts 'Parent info'
  end
end

class [2] < [3]
  def info
    super
    puts 'Child info'
  end
end

Drag options to blanks, or click blank then click option'

AParent

BChild

DAnimal

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the parent class in definition and inheritance.

Not calling super to invoke the parent's method.

The Child class inherits from Parent. The info method in Child calls super to run the parent's info method first.