customer.php

<?php


class Customer
{
   private $firstname;
   private $lastname;
	
   public function __construct(array $data = [])
   {
      list($this->firstname, $this->lastname) = $data;
   }
	
   public function getNameComplete()
   {
     return $this->firstname.' '. $this->lastname;
   }
}

$name = new Customer(['David', 'CHC']);

echo $name->getNameComplete();