"lostinpython" <[EMAIL PROTECTED]> writes:
> I'm having trouble writing a program that figures out a prime number.
> Does anyone have an idea on how to write it? All I know is that n > 2
> is prim if no number between 2 and sqrt of n (inclusivly) evenly
> divides n.
How about this (untested):
import sys
import subprocess
primes = subprocess.Popen(["primes", sys.argv[1], sys.argv[1]],
stdout=subprocess.PIPE).stdout.readlines()
if primes:
print sys.argv[1], "prime"
else:
print sys.argv[1], "not prime"
Seriously, this sounds like a homework assignment. Google for "sieve
of eratosthenes". The BSD "primes" program I used in the above is an
implementation of that in C.
If it isn't a homework assignment, and you're honestly in such, then
you should know there's been a lot of research in this area, because
primes are important in cryptographic applications. Once again, google
is a good place to start on looking for recent research on the subject.
<mike
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Mike Meyer <[EMAIL PROTECTED]> http://www.mired.org/home/mwm/
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