overloading parent methods

[leela]

Hai all,

i have an abstract class , from there i extended the child class, i extended further and made it as final..and i was trying to overload parent methods ..but i cannot overload parent methods using _call..pleadse can anyone help me out..

here is my code :

 

abstract class Shape
{
    protected $length;
    protected $height;
    protected $a;
    protected $b;
    protected $c;
    public function getCoordinates($length,$height)
    {
        $this->length=$length;
        $this->height=$height;
    }
    public function getSides($a,$b,$c)
    {
        $this->a=$a;
        $this->b=$b;
        $this->c=$c;
    }

    abstract public function area();
    abstract public function perimeter();
    abstract public function display();

}

class rectangle extends Shape
{
    public function area()
    {
        return round(($this->length)*($this->height),2);
    }
    public function perimeter()
    {
        return round(2*(($this->a)+($this->b)),2);
    }
    public function display()
    {
        echo "area is :". rectangle::area() . "<br>";
        echo "perimeter is : ". rectangle::perimeter() ."<br>";
    }
}



final class triangle extends rectangle
{
    function __call($method_name, $arguments) // this is wrong ........please modify here to call area(),which is in shape class();
      {
          $accepted_methods = array("getCoordinates","area","perimeter");
      } // this is wrong, i know......i want to overload area() in parent class to overload ..how ?
  
      public function area()
    {
        return round((($this->length)*($this->height)*($this->width)/2),2);
    }
    public function perimeter()
    {
        return round((($this->a)+($this->b)+($this->c)),2);
    }
    public function getCoordinates($length,$height,$width)
     {
         $this->length=$length;
         $this->height=$height;
        $this->width=$width;
      }
    public function display()
    {
        echo "area is :". triangle::area() . "<br>";
        echo "perimeter is : ". triangle::perimeter() ."<br>";
    }
}


$r=new rectangle();
$r->getCoordinates(1,2,4);
$r->getSides(6,2);
$r->display();


$ot = new triangle();
$ot->getCoordinates(1,2,4);
$ot->getSides(6,2,3);
$ot->display();

 

 

thanks in advance ...

[mikesta707]

You can call a parent classes method from a base class by using the scope resolution operator in combination with the parent keyword. using your example

class triangle extends rectangle {
...

public function area(){
//i can call parent by doing this
parent::area();

//i should probably return the value returned by parent though
return parent::area();
}
...
}//end class

 

 

EDIT: actually that would probably call Rectangle's area() method since rectangle is the parent of triangle, not the base class they are both derived from. Let me do a little research and get back to you. The basic idea described above is solid

 

Edit2: After a bit of research, I am unsure if you can access things at the parent's parent's class scope without some ugly hackish type code. One suggestion would be to add a boolean parameter to rectangle's area method which indicates that it would call the parent method instead of doing it normally.

 

for example

class rectangle extends Shape
{
    public function area($callBase = false)
    {
        if ($callBase) return parent::area();
        return round(($this->length)*($this->height),2);
    }
    public function perimeter()
    {
        return round(2*(($this->a)+($this->b)),2);
    }
    public function display()
    {
        echo "area is :". rectangle::area() . "<br>";
        echo "perimeter is : ". rectangle::perimeter() ."<br>";
    }
}



final class triangle extends rectangle
{
    function __call($method_name, $arguments)      {
          $accepted_methods = array("getCoordinates","perimeter");
      }
  
      public function area()
    {
        return parent::area(true);
    }
...
}
...
...

 

While something like this may work, it may be beneficial to review your class structure. Perhaps triangle should inherit from shape. A triangle isn't really a rectangle. Something like Square would be a bitter fit for a child of rectangle. Its about the number of sides, and making triangle a child of rectangle is like making rectangle a child of a 5 or more sided shape, like a pentagon or hexagon. The areas/circumferences/volume/etc. are all calculated differently for shapes of different number of sides.

[KevinM1]

In the future, please post code in either

or

tags.  I took the liberty of doing it for you this time.

[leela]

Thanku so  much......next time, if i post code,definitely i would post code in

 or [code=php:0]

[leela]

hi,

 

here i didnot find any use of _call ? what is the  use.......can i use base class area () for child class triangle and rectangle too ......

 

please tell me