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How would I make a factorial calculator function?

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RohilPatel

How would I make a factorial calculator function? I need that to make a permutations and combinations calculator. I am pretty sure you would need a loop of some sort, but I'm not sure how to do it. Thanks for the help!

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Chiragchachada
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CodyChoo
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RohilPatel
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hotnewtop
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[deleted]

have you tried googling? I found this quite easily: https://www.sitesbay.com/javascript/javascript-factorial-of-number
Do you know about recursion? It can be used instead of a loop: https://www.w3resource.com/javascript-exercises/javascript-recursion-function-exercise-1.php

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RohilPatel

Sort of but not much luck ,

@malvoliothegood

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mwilki7

factorials: n × (n - 1) × (n - 2) ... 2 × 1

you can try using for loop variable to start at n and go to 1
and get something to hold the product of the multiplication inside the loop

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RohilPatel

Wdym?

@mwilki7

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mwilki7

@RohilPatel

this is how you can implement the factorial function on your calculator

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RohilPatel

How do get the number of numbers before hitting 1?

@mwilki7

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SixBeeps

@RohilPatel

image

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mwilki7

@RohilPatel

let product = 1; for (let i = 0; i < n; i++) { product *= i; }
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RohilPatel

Is n the number ur "factorialing" by?

@mwilki7

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mwilki7

@RohilPatel

yes, if i want to find the factorial of 5, n would be 5

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RohilPatel

Hmm, it's not working.

@mwilki7

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mwilki7

@RohilPatel

what are the results you are getting

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RohilPatel

Try it ur self.

@mwilki7

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SixBeeps

@RohilPatel
Make the iterator start from 1 and not 0. Multiplication by 0 just makes the product, well, 0.

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mwilki7

@SixBeeps

shoot how did i miss that

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SixBeeps

@mwilki7
Don't worry, I spent all morning today wondering why my webpage wasn't running. Turns out I spelled "replace" as "replase" :/