queue.rb

class Queue
  def initialize(val)
    @head = Container.new(val)
  end
  
  def add(val)
    temp = Container.new(val)
    head = @head
    loop do
      break unless head.next
      head = head.next
    end
    head.next = temp
    temp.val = val
  end
  
  def remove(val)
    head = @head
    
    loop do
      break unless head.next != nil && head.next.val != val
      head = head.next
    end
    
    if head.next
      head.next = head.next.next
    end
  end
  
  def print
    puts "------------"
    head = @head
    loop do
      puts head.val
      head = head.next
      break unless head
    end
  end
end

class Container
  def initialize(val)
    @val = val
    @next = nil
  end
  
  attr_accessor :val, :next
end

q = Queue.new(3)
q.add(4)
q.add(6)
q.add(19)
q.remove(6)
q.add(8)


q.print
# >> ------------
# >> 3
# >> 4
# >> 19
# >> 8