With inheritance in ruby we can share parent class behavior to child classes. We can also override these methods in child classes.

  A built-in function called super is provided by Ruby. This method allows us to call methods up the inheritance hierarchy. When super is called from within a method, it will search the inheritance hierarchy for a method by the same name and then invoke it.

class Vehicle
  attr_accessor :model, :company

  def initialize(model , company)
    @model = model
    @company = company
  end

  def top_speed
    100
  end
end


class Car < Vehicle

  def top_speed
    150
  end
end


class Bike < Vehicle

  def top_speed
    # passes execution to super class method
    super
  end
end


car = Car.new("Civic", "Honda")
car.top_speed # => 150


bike = Bike.new("Pulsar", "Bajaj")
bike.top_speed # => 100    

In have classes we have Vehicle super class. Car and Bike classes are inheriting from Vehicle. In child classes we have overridden "top_speed" methods. If you noticed in Bike class we have used super in method "top_speed", it class super class method and returns value 100.

Lets pass parameter using super:

class Vehicle
  attr_accessor :model, :company

  def initialize(model , company)
    @model = model
    @company = company
  end

  def top_speed
    100
  end
end


class Car < Vehicle
  attr_reader :color, :engine
  def initialize( engine, color , model , company)
    @engine = engine
    @color = color
    super(model, company)
  end

  def top_speed
    150
  end
end

Here in our Car class we have added two more properties engine and color. We will pass model and company parameters in super.

car = Car.new("petrol", "red", "civic", "honda")
car.color # => "red"
car.company # => "honda"