` Classical fibonaci algorithm

/*
Mathematician  Leonardo Fibonacci posed the following problem in his treatise Liber Abaci (pub. 1202)
How many pairs of rabbits will be produced in a year, beginning with a single pair,
if in every month each pair bears a new pair which becomes productive from the second month on?
*/

int fibmax = 20

int fibonacci(int n)
    int u = 0
    int v = 1
    int t

    for int i in 2 .. n
        t = u + v
        u = v
        v = t
    /for
return v

for int x in 1..fibmax echo "fib(" , x , ") ", fibonacci(x), "\n"