Fatal error after declaring function abstract - php

Question

I have a problem with an error I am getting that says:
Class Car contains 1 abstract method and must therefore be decla
red abstract or implement the remaining methods (Car::accelerate) in C:\xampp
\htdocs\php\learn_php_oop\Car.php on line 58.
This is the code in two files I am using:
Car.php
<?php
/**
* represents generic properties and methods for any type of car
*/
class Car
{
protected $colour, $doorNumber, $fuelType, $rightHandDrive, $accelerate;
public function __construct($rightHandDrive = true)
{
$this->rightHandDrive = $rightHandDrive;
}
public function getColour()
{
return $this->colour;
}
public function setColour($colour)
{
$this->colour = $colour;
}
public function getDoorNumber()
{
return $this->doorNumber;
}
public function setDoorNumber($doorNumber)
{
$this->doorNumber = $doorNumber;
}
public function getFuelType()
{
return $this->fuelType;
}
public function setFuelType($fuelType)
{
$this->fuelType = $fuelType;
}
public function getRightHandDrive()
{
return $this->rightHandDrive;
}
public function setRightHandDrive($rightHandDrive)
{
$this->rightHandDrive = $rightHandDrive;
}
abstract protected function accelerate();
}
?>
Sport_car.php
<?php
include ('Car.php');
/**
* represents sport cars
*/
class Sport_car extends Car
{
public function accelerate()
{
$this->accelerate = 5;
}
}
?>
I have spent some time trying to figure out why this is happening but I just do not know why? Please help.

Answer 1

It's an OOP problem, in your case you must declare your Car Object as Abstract like this :
<?php
/**
* represents generic properties and methods for any type of car
*/
abstract class Car
{
protected $colour, $doorNumber, $fuelType, $rightHandDrive, $accelerate;
public function __construct($rightHandDrive = true)
{
$this->rightHandDrive = $rightHandDrive;
}
public function getColour()
{
return $this->colour;
}
public function setColour($colour)
{
$this->colour = $colour;
}
public function getDoorNumber()
{
return $this->doorNumber;
}
public function setDoorNumber($doorNumber)
{
$this->doorNumber = $doorNumber;
}
public function getFuelType()
{
return $this->fuelType;
}
public function setFuelType($fuelType)
{
$this->fuelType = $fuelType;
}
public function getRightHandDrive()
{
return $this->rightHandDrive;
}
public function setRightHandDrive($rightHandDrive)
{
$this->rightHandDrive = $rightHandDrive;
}
abstract protected function accelerate();
}
?>
Explanations :
A class wich is extended with at least one abstract method in it has to be defined as abstract itself, otherwise you'll get an error