Given the small integer n (0 <= n <= 40) you need to find the n-th number of the alternating Fibonacci sequence.
The sequence starts with 0, 1, -1, 2, -3, 5, -8, 13, -21, ...
So, fib(0) = 0, fib(1) = 1 => fib(2) = -1.Think of the recurrence relation and implement the method named fib in a recursive way. It's not efficient in the general but works well for small n.