PHP/Language Basics/instanceof

Difference between instanceof and is_subclass_of( )

 
<?
    class Dog { }
    class Poodle extends Dog { }
    $poppy = new Poodle( );
    print (int)($poppy instanceof Poodle);
    print "\n";
    print (int)is_subclass_of($poppy, "Poodle");
?>

Using the instanceof Operator

 
<?php
     class Math {
          public function add($op1, $op2) {
               if(($op1 instanceof Float) && ($op2 instanceof Float)) {
                    return $op1->getFloat() + $op2->getFloat();
               } else {
                    echo "Must pass two Floats!\n";
               }
          }
     }
?>