lotus.info.yml

name: Lotus
type: module
description: Lotus module - Task-02 Create a custom page with arguments
core: 8.x
package: Acquia Learning

lotus.routing.yml

lotus.offers_controller_hello:
  path: '/offers/hot/{count}'
  defaults:
    _controller: '\Drupal\lotus\Controller\OffersController::hello'
    _title: 'Offers'
  requirements:
    _permission: 'access content'

OffersController.php

<?php
/** 
* Controller file for Lotus Drupal 8 module. 
* Place this file in src/Controller folder inside the lotus module folder
**/

namespace Drupal\lotus\Controller;

use Drupal\Core\Controller\ControllerBase;

/**
 * Class OffersController.
 *
 * @package Drupal\lotus\Controller
 */
class OffersController extends ControllerBase {

  /**
   * Hello.
   *
   * @return string
   *   Return Hello string.
   */
  public function hello($count) {
    return [
      '#type' => 'markup',
      '#markup' => $this->t('You will get %count% discount!!', array('%count' => $count)),
    ];
  }

}