PHP standard library (SPL)-SPL function ____ function

Array class_implements (mixed $class [, BOOL $autoload])-Returns all interfaces implemented by the specified class.

Array class_parents (mixed $class [, BOOL $autoload])-Returns the parent class of the specified class. int iterator_apply (traversable $iterator, callable $function [, array $args])-Invokes a user-defined function for each element in the iterator
int Iterator_count (traversable $iterator)-Calculates the number of elements in an iterator
Array Iterator_to_array (traversable $iterator [, bool $use = True])-copies elements from an iterator to an array

Example:

<?php 
    Interface foo{}
    class Bar implements foo{}
    class Bar2 extends bar{}
    
    //Return all interfaces
    implemented by the specified class Print_r (new Bar ()) (class_implements);
    
    Returns the parent class Print_r of the specified class
    (class_parents (new bar2));
    
    function _toupper (iterator $iterator) {
        echo strtoupper ($iterator-> current (). " \ n ");
        return TRUE;
    }
    $it = new Arrayiterator (Array ("A" => "Apples", "B" => "Bananas", "C" => "cherries"));
    Invokes a user-defined function for each element in the iterator
    iterator_apply ($it, "_toupper", Array ($it));
    
    Calculates the number of elements in the iterator
    $iterator _count = Iterator_count ($it);
    
    Copies the elements in the iterator to the array
    print_r (Iterator_to_array ($it, FALSE));
    
    Returns all available SPL class
    Print_r (Spl_classes ());