I am facing A PHP Error was encountered - database

Question

When I try to access my website member login area, I experiencing multiple errors those were not there earlier.
Please help me look into it.
A PHP Error was encountered
Severity: Notice
Message: Undefined variable: number
Filename: controllers/Site.php
Line Number: 42
Backtrace:
File:
/home/internetsunivers/2xcash.internetsuniversity.com/application/controllers/Site.php
Line: 42 Function: _error_handler
File: /home/internetsunivers/2xcash.internetsuniversity.com/index.php
Line: 315 Function: require_once A PHP Error was encountered
Severity: Warning
Message: Cannot modify header information - headers already sent by
(output started at
/home/internetsunivers/2xcash.internetsuniversity.com/system/core/Exceptions.php:271)
Filename: helpers/url_helper.php
Line Number: 564
Backtrace:
File:
/home/internetsunivers/2xcash.internetsuniversity.com/application/controllers/Site.php
Line: 50 Function: redirect
File: /home/internetsunivers/2xcash.internetsuniversity.com/index.php
Line: 315 Function: require_once
Following is the code in site.php
<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Site extends MY_Controller {
public function index()
{
$this->header(':::SONNY SERVER:::');
$data['site_name'] = $this->site_name;
$this->load->view('home');
$this->footer();
}
public function about() {
$this->header('About | '.$this->site_name);
$data['site_name'] = $this->site_name;
$this->load->view('about');
$this->footer();
}
public function faq() {
$this->header('FAQ | '.$this->site_name);
$data['site_name'] = $this->site_name;
$this->load->view('faq');
$this->footer();
}
public function support() {
$this->header('Contact Support | '.$this->site_name);
$data['site_name'] = $this->site_name;
$this->load->view('support');
$this->footer();
}
public function login() {
$this->header('Login');
$this->form_validation->set_rules('number', 'Phone Number', 'required');
$this->form_validation->set_rules('password', 'Password', 'required');
if ($this->form_validation->run()) {
if ($this->core_model->login()) {
$query = $this->db->get_where('users', array('number' => $number));
$result = $query->row_array();
$name = $result['name'];
$bank_details = $result['bank_details'];
$session_data = array('number' => $_POST['number'], 'loggedin' => TRUE, 'name' => $name);
$this->session->set_userdata($session_data);
redirect(site_url('dash'));
}
elseif ($this->db->get_where('users', array('number' => $this->input->post('number'), 'is_blocked' => 'true'))->num_rows() > 0) {
$this->session->set_flashdata('error', 'Account has been blocked, contact suppport');
} else {
$this->session->set_flashdata('error', 'Login failed');
}
$this->load->view('login');
} else {
$this->load->view('login');
}
}
public function register() {
$this->header('Register | '.$this->site_name);
$data['site_name'] = $this->site_name;
$this->form_validation->set_rules('name', 'Fullname', 'required');
$this->form_validation->set_rules('number', 'Phone Number', 'required');
$this->form_validation->set_rules('location', 'Location', 'required');
$this->form_validation->set_rules('bundle', 'Bundle', 'required');
$this->form_validation->set_rules('bank_details', 'Bank Details', 'required');
$this->form_validation->set_rules('password', 'Password', 'required');
$this->form_validation->set_rules('c_password', 'Confirm Password', 'required|matches[password]');
if($this->form_validation->run()) {
$this->core_model->register();
//register session
$session_data = array('number' => $_POST['number'], 'loggedin' => TRUE, 'name' => $_POST['name'], 'bank_details' => $_POST['bank_details']);
$this->session->set_userdata($session_data);
$this->session->set_flashdata('msg2', 'Successfully registered');
redirect(site_url('spillover'));
$this->load->view('register');
} else {
$this->load->view('register');
}
$this->footer();
}
public function logout() {
$data = array('number', 'loggedin', 'name');
$this->session->unset_userdata($data);
redirect('login');
}
}