RosettaCodeData/Task/Anonymous-recursion/BASIC256/anonymous-recursion.basic

print Fibonacci(20)
print Fibonacci(30)
print Fibonacci(-10)
print Fibonacci(10)
end

function Fibonacci(num)
	if num < 0 then
		print "Invalid argument: ";
		return num
	end if

	if num < 2 then
		return num
	else
		return Fibonacci(num - 1) + Fibonacci(num - 2)
	end If
end function