--description--

To pass the quiz, you must correctly answer at least 9 of the 10 questions below.

--quizzes--

--quiz--

--question--

--text--

What is recursion in programming?

--distractors--

A method of sorting arrays.

A loop that never ends.

A function that returns undefined.

--answer--

A process in which a function calls itself.

--question--

--text--

Which of the following is an example of recursion?

--distractors--

function factorial(n) {
  let result = 1;

  while (n > 0) {
    result = result * n;
    n--;
  }

  return result;
}

function factorial(n) {
  const arr = Array(n).fill().map((_, i) => i + 1);
  return arr.reduce((acc, curr) => acc * curr, 1);
}

function factorial(n) {
  let result = 1;

  for (let i = n; i > 0; i--) {
    result *= i;
  }

  return result;
}

--answer--

function factorial(n) {
  if (n === 0 || n === 1) {
    return 1;
  }
  return n * factorial(n - 1);
}

--question--

--text--

What will the following function return?

function sum(n) {
  if (n === 0) return 0;
  return n + sum(n - 1);
}
sum(3);

--distractors--

3

0

1

--answer--

6

--question--

--text--

How many times will the mystery function be called?

function mystery(n) {
  if (n <= 1) return 1;
  return mystery(n - 2);
}
mystery(5);

--distractors--

2

5

4

--answer--

3

--question--

--text--

Which of the following is true about recursion?

--distractors--

It should never have a base case.

It should only be used for the Fibonacci sequence.

It should only be used for factorials.

--answer--

It should always have a base case.

--question--

--text--

Which of the following options would be an appropriate base case for the given example?

function countDownToZero(number) {
  // Base case goes here.

  console.log(number);
  countDownToZero(number - 1);
}

--distractors--

if (number > 0) {
  return;
}

if (number !== 0) {
  return;
}

if (number === 0) {
  return;
}

--answer--

if (number < 0) {
  return;
}

--question--

--text--

Why must recursion have a base case?

--distractors--

To ensure the function always has a return value.

To reduce the number of function calls.

To ensure all recursive calls are executed in the correct order and a RecursionError is not thrown.

--answer--

To provide a way for the function to break out of its recursive calls and prevent infinite loops.

--question--

--text--

What will this recursive function do?

function repeatString(str) {
  return str + repeatString(str);
}

--distractors--

Return the string twice.

Return undefined.

Create an empty string.

--answer--

Cause a stack overflow.

--question--

--text--

What is a call stack?

--distractors--

A list of function calls that have been executed.

A list of values that were returned by a function.

A special function used to call a function exactly three times.

--answer--

A data structure that keeps track of function calls and their execution order.

--question--

--text--

What does this recursive function do?

function changeString(str) {
  if (str === "") return "";
  return changeString(str.slice(1)) + str[0];
}

--distractors--

Duplicates a string.

Removes vowels.

Removes spaces.

--answer--

Reverses a string.