Project Euler - Problem 2

' https://projecteuler.net/problem=2

sub main()

    n = 1
    fibn = fib(n)
    sum = 0

    while fibn < 4000000
        if ( fibn mod 2 ) = 0
            sum = sum + fibn
        end if
        n = n + 1
        fibn = fib(n)
    end while

    print "Sum of even fibs: "; sum

end sub


function fib(n) as integer

    if n = 2 return 2
    if n = 1 return 1
    return fib( n - 2 ) + fib( n - 1 )

end function