<?php

class Lotto
{
  protected $_drum = [];
  protected $_count = 8;
  protected $_min = 1;
  protected $_max = 42;

  public function __construct($count = NULL, $min = NULL, $max = NULL)
  {
    if($count)
      $this->_count = $count;
    if($min)
      $this->_min = $min;
    if($max)
      $this->_max = $max;

  }

  public function generateSet()
  {
    if(count($this->_drum) === $this->_count)
      $this->_drum = [];

    do
    {
      $number = $this->generateNumber();
      if( ! in_array($number, $this->_drum))
        $this->_drum[] = $number;
    }
    while(count($this->_drum) < $this->_count);

    return true;
  }

  private function generateNumber()
  {
    return mt_rand($this->_min, $this->_max);
  }

  public function getSet()
  {
    return $this->_drum;
  }

  public function __toString()
  {
    return implode(' ', $this->_drum);
  }

}

$lotto = new Lotto;
for($i = 0; $i < 5; $i++)
{
  if($lotto->generateSet())
    echo $lotto, PHP_EOL;
}