38 lines
650 B
Ruby
38 lines
650 B
Ruby
# This file contains the Ruby code from book of
|
|
# "Data Structures and Algorithms
|
|
# with Object-Oriented Design Patterns in Ruby"
|
|
# by Bruno R. Preiss.
|
|
#
|
|
# Copyright (c) 2004 by Bruno R. Preiss, P.Eng. All rights reserved.
|
|
|
|
class QueueAsLinkedList < Queue
|
|
|
|
def initialize
|
|
super
|
|
@list = SinglyLinkedList.new
|
|
end
|
|
|
|
def purge
|
|
@list.purge
|
|
super
|
|
end
|
|
|
|
def head
|
|
raise ContainerEmpty if @count == 0
|
|
@list.first
|
|
end
|
|
|
|
def enqueue(obj)
|
|
@list.append(obj)
|
|
@count += 1
|
|
end
|
|
|
|
def dequeue
|
|
raise ContainerEmpty if @count == 0
|
|
result = @list.first
|
|
@list.extract(result)
|
|
@count -= 1
|
|
result
|
|
end
|
|
|
|
end |