Source Code: | Run it! |

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<?php //primes.php |©2005 Chuck Bartholomew - All Rights Reserved|
$n=1000; //Upper limit of integers to test
$p[0]=2; //Prime numbers found
$s[0]=2*2; //Squares of prime numbers found
$i=1; //Number of primes found
$a=3; //Current number being tested
//Find all primes less than $n
while($a<=$n){
  $isPrime=True;
  $q=0;
  while(($s[$q]<=$a) AND ($isPrime)){
    if($a==($p[$q]*intval(round($a/$p[$q])))){
      $isPrime=False;
    }
    $q=$q+1;
  }
  if($isPrime){
    $p[$i]=$a;
    $s[$i]=$a*$a;
    $i=$i+1;
  }
  $a=$a+1;
}
$j=0;
//Output list of primes found
while($j<$i){
  echo $p[$j]."<br/>";
  $j=$j+1;
}
?>