You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
69 lines
1.1 KiB
Ruby
69 lines
1.1 KiB
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 StackAsLinkedList < Stack
|
|
|
|
def initialize
|
|
super
|
|
@list = SinglyLinkedList.new
|
|
end
|
|
|
|
def purge
|
|
@list.purge
|
|
super
|
|
end
|
|
|
|
def push(obj)
|
|
@list.prepend(obj)
|
|
@count += 1
|
|
end
|
|
|
|
def pop
|
|
raise ContainerEmpty if @count == 0
|
|
result = @list.first
|
|
@list.extract(result)
|
|
@count -= 1
|
|
return result
|
|
end
|
|
|
|
def top
|
|
raise ContainerEmpty if @count == 0
|
|
return @list.first
|
|
end
|
|
|
|
def each(&block)
|
|
@list.each(&block)
|
|
end
|
|
|
|
attr_reader :list
|
|
|
|
class Iterator < Opus8::Iterator
|
|
|
|
def initialize(stack)
|
|
@position = stack.list.head
|
|
end
|
|
|
|
def more?
|
|
not @position.nil?
|
|
end
|
|
|
|
def succ
|
|
if more?
|
|
result = @position.datum
|
|
@position = @position.succ
|
|
else
|
|
result = nil
|
|
end
|
|
return result
|
|
end
|
|
end
|
|
|
|
def iter
|
|
Iterator.new(self)
|
|
end
|
|
|
|
end |