Creating Function using array_merge - php

Question

It is not checking is that the mentioned field is there or not. Both of the version
First Version:
$error = array();
$field_sets = array('username','password','fullname','repeatpass','email');
foreach($field_sets as $fieldname){
if (!isset($_POST[$fieldname]) || (empty($_POST[$fieldname]) && $_POST[$fieldname] != 0)) {
$error[] = $fieldname;
}
}
Second Version:
(in the includes file)
function check_required_fields ($required_array){
$error = array();
foreach($required_array as $fieldname){
if (!isset($_POST[$fieldname]) || (empty($_POST[$fieldname]) && $_POST[$fieldname] != 0)) {
$error[] = $fieldname;
}
}
return $error;
}
In the Source File:
$error = array();
$required_field = array('username','password','fullname','repeatpass','email');
$error = array_merge($error , check_required_fields($required_field , $_POST));

Answer 1

I found the problem. I accidentally put && in the logic. It should be || instead of &&.
if (!isset($_POST[$fieldname]) || (empty($_POST[$fieldname]) || $_POST[$fieldname] != 0))