Uncaught Error: Cannot call abstract method (PHP Fatal error) -

i extending abstract class has 2 abstract methods. when try instantiate the child class, following error,

 php fatal error:  uncaught error: cannot call abstract method getanswer::getanswer() 

when comment out getanswer() in both parent , child things work fine.

php version: 7.0.2 in xampp, running on wondows 8.1.

parent class file app-getanswer-base.php follows

<?php abstract class getanswer{     abstract public function getanswer($username, $questionnaireid, $questionid);     abstract public function getanswers($username, $questionnaireid); } 

child class file app-getanswer-db-direct.php follows

<?php require_once 'config-db-login.php'; require_once 'app-getanswer-base.php';  class getanswer_sqlselect extends getanswer {      public function getanswer($username, $questionnaireid, $questionid){         return null;     }          public function getanswers($username, $questionnaireid){         $connection = new mysqli(dblogin::$db_hostname, dblogin::$db_username, dblogin::$db_password, dblogin::$db_database);          if ($connection->connect_error) die($connection->connect_error);          $query = "select `questionid`, `answer` `answerstore`.`answers` join  `answerstore`.`participants` b on a.`participantid` = b.`participantid` a.`questionnaireid` = '$questionnaireid' , b.`username`='$username'";          $result = $connection->query($query);         $connection->close();          return $result;         } } 

i think when trying instantiate child class it's calling getanswer() method parent class (getanswer) it's working constructor.

try changing method name else.