/////////////////////////////////////////////Task 6 /////////////////////////////////////////
		ECHO '<H1>Task 6:</H1> <br>';
		
		//Object class Vehicles have 2 properties( make and model )
		class Vehicles{
			
			//The private variables holds the object information locally and
			//can then be accessed by using relevant public get and set methods.
			private $make, $model;
			
			//The construct method sets the object properties when the object is created.
			public function __construct($make, $model){			
				$this->make = $make;
				$this->model = $model;
				echo $this->get_Formatted_Description();
			}
			
			//Set methods if you want to change the make or model
			//you can implement bussiness rules in the set method to prevent data issues.
			//like changing the make if the model is already set could cause an invalid vehicle.
			public function set_Make($NewMake){
				$this->make = $NewMake;
			}
			public function set_Model($NewModel){
				$this->model = $NewModel;
			}
			
			//Get methods if you want to Access the make or model
			//you can implement bussiness rules in the get method to format the output or do
			//Data conversion.
			public function get_Make(){
				return $this->make;
			}
			public function get_Model(){
				return $this->model;
			}
			
			public function get_Formatted_Description(){
				$strRet = "The make is <u>$this->make</u>, the model is the <u>$this->model</u>.";
				return $strRet;
			}
			
		}
		
		//Object class petrol_Vehicles is a subclass of vehicles and inherits from it.
		//thus all properties and methods from Vehicles are in petrol_Vehicles;
		//Petrol_Vehicles extends the current vehicle class by adding fuel properties(Type,TankSize and FuelInTank)
		class petrol_Vehicles extends Vehicles{
			private $Type, $TankSize, $FuelInTank;
			
			public function __construct($make, $model, $Type="Unleaded", $TankSize=55, $FuelInTank=0){
				$this->Type = $Type;
				$this->TankSize = $TankSize;
				$this->FuelInTank = $FuelInTank;
				parent::__construct($make, $model);
			}
			
			//Set methods if you want to change the make or model
			//you can implement bussiness rules in the set method to prevent data issues.
			//like changing the type to electric can be prevented.
			public function set_Type($NewType){
				$this->Type = $NewType;
			}
			
			public function set_TankSize($NewTankSize){
				if ($NewTankSize >=0){
					$this->TankSize = $NewTankSize;
				}
			}
			
			public function set_FuelInTank($NewFuelInTank){
				if ($NewFuelInTank >=0){
					if ($NewFuelInTank <= $this->TankSize){
						$this->FuelInTank = $NewFuelInTank;
					}				
				}
			}
			
			//Get methods if you want to Access the make or model
			//you can implement bussiness rules in the get method to format the output or do
			//Data conversion like change liters to gallons.
			public function get_Type(){
				return $this->Type;
			}
			
			public function get_TankSize(){			
				return $this->TankSize;
			}
			
			public function get_FuelInTank(){
				return $this->FuelInTank;
			}
			
			
		}
		//This creates a new instance of the Petrol_Vehicles class.
		$MyCar = new petrol_Vehicles("Mercedes Benz","500S","Unleaded",60,45);
		echo "<br>";
		
		//ouput the properties of the Petrol_Vehicle instance
		echo "The vehicle is using ". $MyCar->get_Type() ." petrol and has ". $MyCar->get_FuelInTank() ." liters in the ". $MyCar->get_TankSize() ." liter tank.";
		echo "<br>";
		echo "Owner used the car over the weekend and used 5 liters of fuel.<br>";
		//Change some of the properties
		$MyCar->set_FuelInTank($MyCar->get_FuelInTank() - 5);
		
		//ouput the properties of the Petrol_Vehicle instance
		echo "The car has ". $MyCar->get_FuelInTank() ." liters of ". $MyCar->get_Type() ." fuel left in the ". $MyCar->get_TankSize() ." liter tank.";