RosettaCodeData/Task/Fibonacci-sequence/Eiffel/fibonacci-sequence.e

class
   APPLICATION

create
   make

feature

   fibonacci (n: INTEGER): INTEGER
      require
         non_negative: n >= 0
      local
         i, n2, n1, tmp: INTEGER
      do
         n2 := 0
         n1 := 1
         from
            i := 1
         until
            i >= n
         loop
            tmp := n1
            n1 := n2 + n1
            n2 := tmp
            i := i + 1
         end
         Result := n1
         if n = 0 then
            Result := 0
         end
      end

feature {NONE} -- Initialization

   make
         -- Run application.
      do
         print (fibonacci (0))
         print (" ")
         print (fibonacci (1))
         print (" ")
         print (fibonacci (2))
         print (" ")
         print (fibonacci (3))
         print (" ")
         print (fibonacci (4))
         print ("%N")
      end

end