PHP实现的求100以内的质数

在javaeye看到的这个题目：http://www.iteye.com/topic/996233

我用PHP实现了一下

<?php

$pur = array();

for ($i=2; $i<101; $i++){

$flag = false;

for ($j=2; $i<=4 ? $j<$i : $j<=$i/2; $j++){

if ($i % $j == 0){

$flag = false;

break 1;

}else{

$flag = true;

}

}

if($flag){

array_push($pur, $i);

}

}

echo "<pre>",print_r($pur),"</pre>";

?>

输出：

Array
(
[0] => 3
[1] => 5
[2] => 7
[3] => 11
[4] => 13
[5] => 17
[6] => 19
[7] => 23
[8] => 29
[9] => 31
[10] => 37
[11] => 41
[12] => 43
[13] => 47
[14] => 53
[15] => 59
[16] => 61
[17] => 67
[18] => 71
[19] => 73
[20] => 79
[21] => 83
[22] => 89
[23] => 97
)