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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.

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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!

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[erix]: *rare commodity
[shmem]: erix: you are utterly mistaken in marking that site as "pro-russian".
[erix]: how do you mean? the bear, explanations of Putin's "election", the fearsome new russian weaponry. I came across them immediately. Just coincidence?
[shmem]: No, not coincidence - prejudice and bias
[shmem]: your scanner is pre-loaded ;-)

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