Define an interface which has methods area(), volume(). Define constant PI. Create a class cylinder which implements this interface and calculate area and volume.

                           

Define an interface which has methods area(), volume(). Define constant

PI. Create a class cylinder which implements this interface and calculate

area and volume. (Hint: Use define())

 <?php 

define('PI','3.142');

interface cal

{

function area();

function volume();

}

class cylinder implements cal

{

var $r;

var $h;

function setValue($r,$h)

{

$this->r=$r;

$this->h=$h;

}

function area()

{

$a=2*PI*$this->r*($this->r+$this->h);

echo "AREA OF CYLINDER= :$a";

echo "<br>";

}

function volume()

{

$v=PI*$this->r*$this->r*$this->h;

echo "VOLUME OF CYLINDER= :$v";

echo "<br>";

}

}

$c=new cylinder();

$c->setValue(2,3);

$c->area();

$c->volume();

?>