Skip to content

Instantly share code, notes, and snippets.

@p01

p01/LICENSE.txt

Forked from 140bytes/LICENSE.txt
Created July 30, 2011 11:27
Show Gist options
  • Star 4 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save p01/1115434 to your computer and use it in GitHub Desktop.
Save p01/1115434 to your computer and use it in GitHub Desktop.
Download ZIP
isPrimeNumber in 41 bytes
Raw
README.md
Raw
annotated.js
function(
n, // the number
i // placeholder counter
){
for(i=n;n%--i;); // keeps going until the modulo is falsy like n%1 for instance
return i<2
}
Raw
index.js
function(n,i){for(i=n;n%--i;);return i<2}
Raw
LICENSE.txt
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2011 Mathieu 'p01' Henri <http://www.p01.org/releases/>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.
Raw
package.json
{
"name": "isPrimeNumber",
"description": "Check if a number is prime in 41bytes.",
"keywords": [
"isPrimeNumber",
"prime",
"number"
]
}
Raw
test.html
<!DOCTYPE html>
<title>isPrimeNumber</title>
<div>Expected values: <b>false,true</b></div>
<div>Actual value: <b id="ret"></b></div>
<script>
var myFunction = function(n,i){for(i=n;n%--i;);return i<2};
document.getElementById( "ret" ).innerHTML = myFunction(140)+','+myFunction(541);
</script>
@tsaniel
Copy link

tsaniel commented Feb 28, 2012

@mattneary: I think even JavaScript could handle large numbers, your code won't work.
Because some non-prime numbers (e.g. 341) can pass the test.

@tsaniel
Copy link

tsaniel commented Feb 28, 2012

I mean the theorem cannot tell whether a number is really a prime number or not, 341 is an example(It passes the test even it is not a prime number).

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment