php - php程序中的错误

Question

我只是 PHP 的初学者。我曾尝试为素数编写程序，但结果不正确。我找不到错误。我该如何纠正？这是我的代码:

<?php
$n=15;
for($i=2; $i<=$n; $i++)
{
echo "<br />";
for($j=2; $j<=$i-1; $j++)
    {
        $k=$i%$j;
        if($k==0)
        {

        break;
        }
        else echo $i."is prime";
        break;
    }

}
?>

Answer 1

尝试这个:

        <?php
        $n=15;
        for($i=2; $i<=$n; $i++)
        {
            $k = 1;     //assume that it is prime

            for($j=2; $j<$i; $j++)  //if $i is 2, then it won't enter the loop as it will not match the condition ($j<$i)
            {
                $k=$i%$j;
                if($k==0) 
                    break;  //if not prime, $k will be set as 0. So, break.

            }
            if($k!=0)   // if $k <> 0, then it is prime
                echo "<br />" . $i." is prime";
        }

        ?>

编辑
更新了代码以处理“2”