freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/rosetta-code/factorial.md

id, title, challengeType, forumTopicId

id	title	challengeType	forumTopicId
597b2b2a2702b44414742771	Factorial	5	302263

--description--

Write a function to return the factorial of a number.

Factorial of a number is given by:

n! = n * (n-1) * (n-2) * ..... * 1

For example:

• 3! = 3 * 2 * 1 = 6
• 4! = 4 * 3 * 2 * 1 = 24

Note: 0! = 1

--hints--

factorial should be a function.

assert(typeof factorial === 'function');

factorial(2) should return a number.

assert(typeof factorial(2) === 'number');

factorial(3) should return 6.

assert.equal(factorial(3), 6);

factorial(5) should return 120.

assert.equal(factorial(5), 120);

factorial(10) should return 3,628,800.

assert.equal(factorial(10), 3628800);

--seed--

--seed-contents--

function factorial(n) {

}

--solutions--

function factorial(n) {
  let sum = 1;
  while (n > 1) {
    sum *= n;
    n--;
  }
  return sum;
}