This code is quite fast, since it skips a lot of unnecessary operations
#!/usr/bin/perl

use strict;
use warnings;
use POSIX;

my ($i,$j,$h,$sentinel) = (0,0,0,0);

# i>=3
for($i=1000000000; $i<=1000000500; $i++){
 # if $i is an even number, it can't be a prime
 if($i%2==0){}
 else{
  $h=POSIX::floor(sqrt($i));
  $sentinel=0;
     # since $i can't be even -> only divide by odd numbers
     for($j=3; $j<=$h; $j+=2){
         if($i%$j==0){
             $sentinel++;
             # $i is not a prime, we can get out of the loop
             $j=$h;
         }
     }
  if($sentinel==0){
   print "$i \n";
  }
 }
}

[download]

In reply to Re^4: Prime Number Finder by Anonymous Monk
in thread Prime Number Finder by munchie

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