字符串类型整形转化

$str = '150.2';
$str_s = $str * 100;
echo $str_s;
echo "-------";
echo (int)($str * 100);
echo '****--';
echo (int)($str_s);
echo '****--';
echo (int)(15020);
exit;


15020-------15019****--15019****--15020