kuchen.rb

class SliceOfCake
   @@totalSlices = 0
   def initialize 
     @@totalSlices +=1
   end 
   def getNumberOfSlices
     if(@@totalSlices == 0)
      "sorry no slices yet"
     elsif (@@totalSlices == 1)
      "there is #{@@totalSlices} slice of cake"
     else
      "there are #{@@totalSlices} slices of cake"
      end 
   end
end   

slice = SliceOfCake.new
slice2 = SliceOfCake.new

puts slice.getNumberOfSlices  #=>  there are 2 slices of cake
puts slice2.getNumberOfSlices  #=> there are 2 slices of cake