class CD
include Comparable
@@plays = 0
attr_reader :name, :artist, :duration
attr_writer :duration
def initialize(name, artist, duration)
@name = name
@artist = artist
@duration = duration
@plays = 0
end
def to_s
"CD: #@name--#@artist (#@duration)"
end
def inspect
self.to_s
end
def <=>(other)
self.duration <=> other.duration
end
end
class NewCD < CD
def initialize(name, artist, duration, lyrics)
super(name, artist, duration)
@lyrics = lyrics
end
def to_s
super + " [#@lyrics]"
end
end
class NewCD
def to_s
super
end
end
d = NewCD.new("A", "S", 1, "C")
d.to_s