% Recursive
function fibb (n: int) : int
    if n < 2 then
        result n
    else
        result fibb (n-1) + fibb (n-2)
    end if
end fibb

% Iterative
function ifibb (n: int) : int
    var a := 0
    var b := 1
    for : 1 .. n
        a := a + b
        b := a - b
    end for
    result a
end ifibb

for i : 0 .. 10
    put fibb (i) : 4, ifibb (i) : 4
end for