Online PHP editor | output for eqf7T

<?php class induk { protected function alas() { return "Alas"; } protected function miring() { return "Miring"; } } // turunkan class induk ke anak class anak extends induk { protected function tinggi() { return "Tinggi"; } } // turunkan class anak ke cucu class cucu extends anak { protected function luas() { return "Luas"; } public function pewarisan(){ $a = $this->alas(); $b = $this->miring(); $c = $this->tinggi(); $d = $this->luas(); return "$a -> $b -> $c -> $d"; } } // buat objek dari class cucu (instansiasi) $new_pewarisan = new cucu(); //panggil method objek echo $new_pewarisan->pewarisan(); // $new_pewarisan->induk(); // Fatal error: Call to protected method komputer::induk() ?>