Ruby | Method overriding

Method is a collection of statements that perform some specific task and return the result. Override means two methods having same name but doing different tasks. It means that one of the methods overrides another method. If there is any method in the superclass and a method with the same name in its subclass, then by executing these methods, method of the corresponding class will be executed. Example :

Ruby

# Ruby program of method overriding

# define a class
class A
  def a
    puts 'Geeks'
  end
end

# define a subclass
class B < A

  # change existing a method as follows
  def a
    puts 'Welcome to GeeksForGeeks'
  end
end

b = B.new
b.a

Output :

Welcome to GeeksForGeeks

In above Example, Execution of a on the object of A printed Geeks from the a method defined in the A class whereas, execution of a on the object of B printed Welcome to GeeksForGeeks from the a method defined in the B class. It is very useful because it prevents us from making methods with different names and remembering that all. The method a in class B overrides the method a in class A. Example :

Ruby

# Ruby program of method overriding

# define a class
class Box
   # constructor method
   def initialize(width, height)
      @w, @h = width, height
   end
   # instance method
   def getArea
      @w * @h
   end
end

# define a subclass
class BigBox < Box

   # change existing getArea method as follows
   def getArea
      @area = @w * @h
      puts "Big box area is : #@area"
   end
end

# create an object
box = BigBox.new(15, 20)

# print the area using overridden method.
box.getArea()

Output:

Big box area is : 300

In above example, The method getArea in class BigBox overrides the method getArea in class Box.