View difference between Paste ID: eFMVjzcE and FKEFdnhK

 <?php
 
 	// class that extends abstract method must define all abstract declared methods
 
 	/**
 	 * Polymorphism describes a pattern in object oriented programming
 	 * in which classes have different functionality while sharing a common interface.
 	 * refer to http://net.tutsplus.com/tutorials/php/understanding-and-applying-polymorphism-in-php/
 	 * http://www.easylearntutorial.com/2012/11/advanced-php-tutorial-what-is-polymorphism.html#.UeUwgkAyagZ
 	 * 	 	OR
 	 * page 44 of Object oriented Programming with php : PACKT
 	 */
 
 
 	abstract class Shape
 	{
 		private $_color = "black";
 		private $_filled = false;
 
 		public function getColor()
 		{
 			return $this->_color;
 		}
 
 		public function setColor( $color )
 		{
 			$this->_color = $color;
 		}
 
 		public function isFilled()
 		{
 			return $this->_filled;
 		}
 
 		public function fill()
 		{
 			$this->_filled = true;
 		}
 
 		public function makeHollow()
 		{
 			$this->_filled = false;
 		}
 
 		abstract public function getArea();  // define this method in any class that extends it
 
 	}  // End of abstact class MyAbstract
 
 	class Rectangle extends Shape
 	{
 		private $_width = 0;
 		private $_height = 0;
 
 		public function getWidth()
 		{
 			return $this->_width;
 		}
 
 		public function getHeight()
 		{
 			return $this->_height;
 		}
 
 		public function setWidth(  $width  )
 		{
 			$this->_width = $width;
 		}
 
 		public function setHeight( $height )
 		{
 			$this->_height = $height;
 		}
 
 		public function getArea()
 		{
 			return $this->_height * $this->_width;
 		}
 
 	}  // End of class Rectangle , extending Shape
 
 	echo "<pre>";
 
 	$r = new Rectangle();
 
 	$r->setWidth(10);
 	$r->setHeight(20);
 
 	echo $r->getWidth() . "<br>" ;
 	echo $r->getHeight() . "<br>" ;
 
 	echo $r->getColor() . "<br>";
 	$r->setColor("Green");
 	echo $r->getColor()  . "<br>";
 
 	var_dump( $r->isFilled() ) ;
 
 	$r->fill();
 
 	var_dump( $r->isFilled() ) ;
 
 	$r->makeHollow();
 
 	var_dump( $r->isFilled() ) ;
 
 	echo"</pre>";
 ?>