Recursion in Java (AP Computer Science A)

When the base case is met, which of these could be returned?

[Enclosing method: recursiveFunc(int n)]

• return recursiveFunc(n + 1);

• return (double) 1000;

• return n * recursiveFunc(n);

• return recursiveFunc(n) - 1;

The capabilities of a recursive function can typically be recreated by . . .

• If / Else statements

• Classes

• Loops

• Interfaces

For which of these operations is a recursive function practical?

• Scanning user input

• Finding the sum of two integers

• Returning the first item of a list

• Calculating the factorial of an integer

What is a recursive function?

• Function that returns once

• Function that creates objects

• Function that calls itself

• Function needing abstraction to be used

Which of these is NOT an acceptable header for a recursive function?

• public void recursiveFunc(Object obj) {

• public int recursiveFunc(int n) {

• public double recursiveFunc(double n) {

• public String recursiveFunc(String str) {

Assuming n is initialized as an integer variable with a positive value, what will be printed?

• The factorial of n

• The absolute value of n

• The sum of all digits in n

• The square root of n

The Collatz Conjecture states that, in sequence, taking any integer and, if even, halving the result/integer and, if odd, tripling and adding 1 to the result/integer continuously will eventually end up as 1.

Which of the above methods properly recreates the conjecture?

Select all answers that apply.

(Click the picture to enlarge.)

• recursiveCollatz1(int n)

• recursiveCollatz2(int n)

• recursiveCollatz(int n)

• None

Which of the above methods correctly implements indirect recursion?

Select all answers that apply.

• recursiveCollatz1(int n)

• recursiveCollatz2(int n)

• recursiveCollatz(int n)

• None

Which of the above methods correctly implements direct recursion?

Select all answers that apply.

• recursiveCollatz1(int n)

• recursiveCollatz2(int n)

• recursiveCollatz(int n)

• None

Which of the above methods could result in a stack overflow exception for certain values of n?

Select all answers that apply.

• recursiveCollatz1(int n)

• recursiveCollatz2(int n)

• recursiveCollatz(int n)

• None