Online PHP editor | output for FqUPH

<?php class Record { protected $index=0; //page index protected $pages=[]; //pages array public function nextPage() { $this->index++; } public function addRecord($key, $value) { $this->pages[$this->index][$key] = $value; } public function getPage($index) { if ($index > $this->index) return NULL; else return $this->pages[$this->index]; } } class AdditiveRecord extends Record { private function getSums($range) { $sums = $this->pages[$range[0]]; $lim = ($range[1] <= $this->index) ? $range[1] : $this->index; for ($i = $range[0]+1;$i<$lim;$i++) { foreach($this->pages[$i] as $k=>$v) $sums[$k] += $v; } return $sums; } } $m = new AdditiveRecord(); for ($j = 1;$j<3;$j++) { for ($i = 1;$i<10;$i++) $m.addRecord($i,$j*10+$i); $m->nextPage(); } $m->getSums([0,1]);