AP CSA Recursion 3

Question 1

What is a recursive method that counts down from n printing each number called?

Accepted Answer

Linear recursion

Answer

A method making a single recursive call per invocation, working through a linear sequence, is called linear recursion.

Question 2

What must be true about the argument in each recursive call to guarantee termination?

Accepted Answer

It must move closer to the base case

Answer

Each recursive call must use an argument that brings it closer to the base case, ensuring eventual termination.

Question 3

How many total method calls does factorial(4) make (including the initial call)?

Accepted Answer

5

Answer

factorial(4) calls factorial(3), which calls factorial(2), factorial(1), and factorial(0) — 5 calls total including the first.

Question 4

Which of the following is NOT an advantage of recursion?

Accepted Answer

Always more memory-efficient than iteration

Answer

Recursion is not always more memory-efficient; each call uses stack space, so deep recursion can use more memory than iteration.

Question 5

What is 'unwinding the stack' in recursion?

Accepted Answer

The process of returning from recursive calls back to the original caller

Answer

Stack unwinding is when recursive calls finish and return in reverse order, passing values back up to the original caller.

AP CSA - Advanced Placement Computer Science A Practice Test