Question

The following is a recursive function:

def countdown(n): if n == 0: return else: countdown(n - 1) countdown(5)

In 3-5 sentences, explain the algorithm.

Answer 1

The `countdown` function is a recursive algorithm that counts down from a given integer `n` to 0. If `n` is equal to 0, the function simply returns, which serves as the base case for the recursion and stops further calls. If `n` is greater than 0, the function calls itself with the argument `n - 1`, effectively reducing the value of `n` by 1 for each recursive call. When `countdown(5)` is invoked, it will recursively call itself until it reaches 0, executing five recursive calls in total. However, since there is no output statement in the function, it doesn’t produce any visible output for the countdown process.