第 20 行:$this->data['available_credits'] = $total_credits - $used_credits;
function index() {
$user_id = $this->session->userdata('user_id');
$this->data['credits'] = $this->credit_m->get_credit_details($user_id);
$total_credits = $this->data['total_credits'] = $this->credit_m->get_total_credits($user_id);
$used_credits = $this->data['used_credits'] = $this->credit_m->get_used_credits($user_id);
$this->data['available_credits'] = $total_credits - $used_credits;
$this->template->build('credits_view',$this->data);
}