switch语句怎么运行不了

Question

switch($type) {
case 'image/pjpeg' : $ok=1;
break;
case 'image/jpeg' : $ok=1;
break;
case 'image/gif' : $ok=1;
break;
case 'image/png' : $ok=1;
break;
}
if($ok){
move_uploaded_file($tmp_name,'up/'.$name);
}
这是按视频上写的代码，为啥显示Undefined variable: ok in C:\wamp\www\bbs2\up2.php on line 20？求解答，先谢过了。

Answer 1

http://www.jb51.net/article/32127.htm

 $ok=false;////////
switch($type) {