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Ruby Constructors

The important constructor method is the initialize method.

Simple Example

# Ruby program to initialize instance # variable using constructor #!/usr/bin/ruby # class name class Geeks # constructor def initialize # instance variable intialzation @inst_1 = "GeeksforGeeks" @inst_2 = "Sudo Placement" end # display method def display puts "Value of First instance variable is: #{@inst_1}" puts "Value of Second instance variable is: #{@inst_2}" end end # creating object obj1 = # calling display method obj1.display()

Linked List Example

""" Basic implementation without all methods """ class LinkedList def initialize(head=nil) if head.nil? @size = 0 else @size = 1 end @head = head end def getSize @size end def insertFirst(n) if @head.nil? @head = n else tmp = @head @head = n n.setNext(tmp) end @size += 1 end def clear @head = nil @size = 0 end def getFirst @head end end class Node def initialize(data = nil) @data = data @next = nil end def getNext @next end def setNext(n) @next = n end end # test Ruby file begin gem 'minitest', '>= 5.0.0' require 'minitest/autorun' require_relative 'linked_list' rescue Gem::LoadError => e puts "\nMissing Dependency:\n#{e.backtrace.first} #{e.message}" puts 'Minitest 5.0 gem must be installed for the Ruby track.' rescue LoadError => e puts "\nError:\n#{e.backtrace.first} #{e.message}" puts exit 1 end # Common test data version: 1.1.0 be3ae66 class LinkedListTest < Minitest::Test def test_get_size # skip n1 = ll = assert_equal 1, ll.getSize() end def test_insert_first # skip n1 = n2 = ll = ll.insertFirst(n2) assert_equal 2, ll.getSize() end def test_clear # skip n1 = n2 = ll = ll.insertFirst(n2) ll.clear() assert_equal 0, ll.getSize() assert_nil nil, ll.getFirst() end end __END__

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Dennis O'Keeffe

  • Melbourne, Australia

Hi, I am a professional Software Engineer. Formerly of Culture Amp, UsabilityHub, Present Company and NightGuru.
I am currently working on, Den Dribbles and LandPad .


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