Recursion Flashcards
6 cards from real AP CSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Recursion flashcards as text
What is the base case in a recursive method?
Answer: The condition that stops the recursion
The base case is the condition that terminates recursion by returning a result without making further recursive calls.
What error occurs when a recursive method has no base case or never reaches it?
Answer: StackOverflowError
Infinite recursion causes the call stack to fill up, resulting in a StackOverflowError at runtime.
What does the following return? `public int f(int n) { if(n==0) return 0; return n + f(n-1); }` called with f(4)?
Answer: 10
f(4) = 4 + f(3) = 4+3+2+1+0 = 10, computing the sum of integers from 0 to n.
In recursion, each method call gets its own set of local variables stored where?
Answer: On the call stack
Each recursive call creates a new stack frame on the call stack that holds its own local variables and parameters.
Which of the following best describes mutual recursion?
Answer: Two methods that each call the other
Mutual recursion occurs when method A calls method B and method B calls method A, forming a cycle.
What is the recursive case?
Answer: The part of the method that makes a call to itself with a smaller/simpler input
The recursive case is the branch that calls the method again with a modified argument, moving toward the base case.