rem - iterative function to calculate nth fibonacci number
function fibonacci(n = integer) = integer
var f, i, p1, p2 = integer
p1 = 0
p2 = 1
if n = 0 then
   f = 0
else
   for i = 1 to n
      f = p1 + p2
      p2 = p1
      p1 = f
   next i
end = f

rem - exercise the function
var i = integer
for i = 0 to 10
   print fibonacci(i);
next i

end