php中的对象有问题

    $user1 = mysql_fetch_object(mysql_query("SELECT * FROM tbl WHERE username='$oc->user1'"));      
    $user2 = mysql_fetch_object(mysql_query("SELECT * FROM tbl WHERE username='$oc->user2'"));
    $user3 = mysql_fetch_object(mysql_query("SELECT * FROM tbl WHERE username='$oc->user3'"));

我可以通过这样做获得user1的位置: $location = $user1->location ,但我想创建一个包含所有用户位置的数组,我尝试了以下方法:

        for ($x = 0 ; $x < $users_total; $x++ ){

        $user = "user".($x + 1);            
        $user_location[$x] = $user->location ; //array med stedet alle brukerne befinner seg    

        } 

这应该叫 $user1->location $user2->location , $user3->location 到数组[0][1]和[3]。但是我得到了

Notice: Trying to get property of non-object

"user".($x + 1); 打电话给那个地方 $user->location . 这不就是 ?