Python Recursion: Quick Check

Review

1. What is the main purpose of a base case in a recursive function?

   The base case handles a problem directly so the recursive chain has a stopping point.
2. In sum_to(3), which call finishes first?

   sum_to(3) calls sum_to(2), which calls sum_to(1), which calls sum_to(0); the base case at zero returns first.
3. When a recursive function is called again, what happens to its local variables?

   Each function call has its own local namespace, so recursive invocations can hold different parameter and local values.
4. What exception does Python raise when it detects that the maximum recursion depth has been exceeded?

   Python raises RecursionError when it detects that the maximum recursion depth has been exceeded.
5. Which task is the strongest fit for recursion?

   Nested tree-like data naturally contains smaller structures of the same form, which makes recursive traversal a natural fit.