Newbie question - pointer in a code

$is_author = $account->uid == $node->uid;

what is that mean?
Does pointer are mean to set a value or get a value?

*that is from the pro drupal development book.

that is the FULL code:

function job_post_node_access($op, $node, $account) {
$is_author = $account->uid == $node->uid;
switch ($op){
case 'create':
if (user_access('create job',$account)){
return NODE_ACCESS_ALLOW;
}
case 'update':
if (user_access('edit own job', $account) && $is_autor ||
user_access('edit any job' ,$account)) {
returm NODE_ACCESS_ALLOW;
}
case 'delete':
if (user_access('delete own job', $account) && $is_author
|| user_access('delete', $account)) {
return NODE_ACCESS_ALLOW;
}
}
}