Codeigniter Undefined property: Welcome::$session and Call to a member function flashdata() on null

Question

Im using a Codeigniter but why am I getting these error (1) Message: Undefined property: Welcome::$session (2) Message: Call to a member function flashdata() on null

Do I need to add something? Thank you

Thank you

Error

<?php

defined('BASEPATH') OR exit('No direct script access allowed');

class Welcome extends CI_Controller {

public function index()
{
    $this->load->view('home');
}

function registerNow()
{

    if($_SERVER['REQUEST_METHOD']=='POST')
    {
        $this->form_validation->set_rules('fname', 'First Name', 'required|alpha');
        $this->form_validation->set_rules('mname', 'Middle Name', 'required|alpha');
        $this->form_validation->set_rules('lname', 'Last Name', 'required|alpha');
        $this->form_validation->set_rules('username', 'Username', 'required');
        $this->form_validation->set_rules('password', 'Password', 'required|min_length[8]');
        $this->form_validation->set_rules('confirmpass', 'Confirm Password', 'required|min_length[8]|matches[password]');
        $this->form_validation->set_rules('bday', 'Birthday', 'required');
        $this->form_validation->set_rules('email', 'Email', 'required|valid_email');
        $this->form_validation->set_rules('contact', 'Contact Number', 'required|numeric');

        if($this->form_validation->run()==TRUE)
        {
            $fname = $this->input->post('fname');
            $mname = $this->input->post('mname');
            $lname = $this->input->post('lname');
            $username = $this->input->post('username');
            $password = $this->input->post('password');
            $bday = $this->input->post('bday');
            $email = $this->input->post('email');
            $contact = $this->input->post('contact');

            $data = array(
                'first_name'=>$fname,
                'middle_name'=>$mname,
                'last_name'=>$lname,
                'username'=>$username,
                'password'=>sha1($password),
                'bday'=>$bday,
                'email'=>$email,
                'contact_number'=>$contact  
            );

            $this->load->model('user_model');
            $this->user_model->insertuser($data);
            $this->session->flashdata('success','Successfully User Created');
            redirect(base_url('welcome/index'));
        }
    }
}

}

Answer 1

call the session on your controller to use session

$this->load->library('session');

Or go to application\config\autoload.php

and add session to the array

$autoload['libraries'] = array('session');