Factoralize a Number in JavaScript

Question

I'm currently taking a course on Free Code Camp and it's asking me return a factorial for any given number. However, I'm kind of stuck on the question (please forgive me, math isn't my strong point, haha). Here's what it asks:

If the integer is represented with the letter n, a factorial is the product of all positive integers less than or equal to n. Factorials are often represented with the shorthand notation n! For example: 5! = 1 * 2 * 3 * 4 * 5 = 120f

And here's the starting code:

function factorialize(num) {
return num;
}

factorialize(5);

I'm not looking for a direct answer to the question, but I just really want to know how to start. Thanks for any help in advance!

Answer 1

There is two ways of doing that. First one in the loop and second one is in recursive function.

Loop version is like that:

function factorialize(num) {

  for(var answer=1;num>0;num--){
    answer*=num;
  }

  return answer;
}

And recursive one is like that.

function factorialize(num) {

  if(num===0){
    return 1;
  }
  else{
    return num*factorialize(num-1);
  }
}

Both of them will work with all positive integers.