Javascript Factorial Function w/Recursion

This is a fun quick one that you can do right in the Firefox browser, like I did! Open up Firefox, press F12 to open the developer tools, and open the scratchpad. If you don’t see it, don’t worry; you can show it in the Toolbox Options under Default Developer Tools.

As the title says, this is a function that calculates the factorial function of an integer. For those of you who haven’t had to calculate a factorial since high school *cough* me *cough cough*, the factorial function (symbol: !) says to multiply a series of descending natural numbers. For instance, if we wanted to calculate 4!, we would multiply 4 * 3 * 2 * 1 to get our answer. Simple enough, right? Wait until you see the code to do this; it’s mind boggling how simple it is:

The first thing we do is declare our function name, followed by the check of our number to see if it’s greater than 0. If it is, we call the very same function we are inside of but we pass the next descending number in our list of integers. Once we reach 0, we stop multiplication. Then call our function with different numbers to test it out. Easy enough, right?

I’m aware that this is a simple problem but a friend had pointed out some crazy ways that this problem was solved and I wanted to take a quick shot at it. I had fun with it and I hope you do too. If you’ve got a creative solution, post it in the comments below!

Dylan Hildenbrand

profile for Dylan Hildenbrand on Stack Exchange, a network of free, community-driven Q&A sites

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