Three Ways to Factorialize a Number in JavaScript
This article is based on Free Code Camp Basic Algorithm Scripting “Factorialize a Number”
In mathematics, the factorial of a non-negative integer n can be a tricky algorithm. In this article, I’m going to explain three approaches, first with the recursive function, second using a while loop and third using a for loop.
We have already seen a recursion approach on a String in the previous article, How to Reverse a String in JavaScript in 3 Different Ways ? This time we will apply the same concept on a number.
Algorithm Challenge
Return the factorial of the provided integer.
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 = 120
Provided test cases
- factorialize(0) should return 1
- factorialize(5) should return 120
- factorialize(10) should return 3628800
- factorialize(20) should return 2432902008176640000
What is factorializing a number all about?
When you factorialize a number, you are multiplying that number by each consecutive number minus one.
If your number is 5, you would have:
5! = 5 * 4 * 3 * 2 * 1
The pattern would be:
0! = 1
1! = 1
2! = 2 * 1
3! = 3 * 2 * 1
4! = 4 * 3 * 2 * 1
5! = 5 * 4 * 3 * 2 * 1
1. Factorialize a Number With Recursion
Without comments:
2. Factorialize a Number with a WHILE loop
Without comments:
3. Factorialize a Number with a FOR loop
Without comments:
“How to Solve FCC Algorithms” is a series of articles on the Free Code Camp Algorithm Challenges where I try to propose several solutions and explain step by step what happens behind the hood.
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