week7_kadai4.rb

yamanote = ["大崎","五反田","目黒","恵比寿","渋谷","原宿","代々木","新宿","新大久保","高田馬場","目白","池袋","大塚","巣鴨","駒込","田端","西日暮里","日暮里","鶯谷","上野","御徒町","秋葉原","神田","東京","有楽町","新橋","浜松町","田町","品川"]


class ArrayIterator
  def initialize(array)
    @array = array
    @index = 0
  end

  def item
    @array[@index]
  end

  def soto_mawari
    value = @array[@index]
    @index = (@index == @array.length - 1) ? 0 : @index + 1
    value
  end

  def uchi_mawari
    value = @array[@index]
    @index = (@index == 0) ? @array.length - 1 : @index - 1
    value
  end
end

iter = ArrayIterator.new(yamanote)

# (0..30).each do |_|
#   puts "#{iter.soto_mawari}"
# end

(0..30).each do |_|
  puts "#{iter.uchi_mawari}"
end