Beefy Boxes and Bandwidth Generously Provided by pair Networks Ovid
Pathologically Eclectic Rubbish Lister
 
PerlMonks  

Re: is it prime?

by JavaFan (Canon)
on May 06, 2012 at 05:39 UTC ( #969111=note: print w/ replies, xml ) Need Help??


in reply to is it prime?

It cannot be correct. Have you actually tried this? Considering that any number is divisible by 1, isPrime will return 1 for each number. A fix is easy, have $i start at 2.

But then you are still far from being efficient. There's no need to loop to $num/2, you can stop at sqrt($num). There's no need to test even numbers (except 2). And there's no need to continue once you've found a divisor.


Comment on Re: is it prime?
Re^2: is it prime?
by Anonymous Monk on May 06, 2012 at 05:44 UTC
    i did test it, you are correct it is incorrect i was hoping for a fix (hence why i posted) thanks for the help
      also you are right again i dont need a loop hell knows why i was using one sinse im only sending 1 arg (digit) at a time to the sub routine :/
        no.. above was wrong.. jeez now i dont know what im talking about haha this isnt going good :/ not slept all night is my excuse!

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://969111]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others musing on the Monastery: (7)
As of 2014-04-17 22:18 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    April first is:







    Results (458 votes), past polls