这段php代码为什么没效果？

Question

 <?php
$dbhost='';
$dbname='';
$dbuser='';
$dbpass='';
date_default_timezone_set('PRC');
try{$pdo=new PDO('mysql:host='.$dbhost.';dbname='.$dbname,$dbuser,$dbpass);}
catch(Exception $e){die('sql error');}
$pdo->query('SET NAMES utf8');
function cd(){global $pdo;return $pdo->lastInsertId();}
function qr($var){global $pdo;return $pdo->query($var);}
function fo($var){return qr($var)->fetch();}
function fa($var){return qr($var)->fetchALL();}
$fp=fo('SELECT * FROM post WHERE id='.$p);
echo $fp['title'];
echo $fp['content'];
?>_

Answer 1

看看代码调用了没有，是不是有错误