how create recursive class function trace path between related objects?
data:
id name parentid 1 egypt 0 2 usa 0 3 giza 1 4 6th october 3 function call such addresspath(4) should produce output:
egypt->giza->6th october
today posted terse homework-looking question did not show research effort, , had gratuitous number of downvotes. encouraged answer type of question because of this answer, , i've found reasonable enjoyment , sharpening of skills result (think code kata). however, post deleted before post answer, maybe because of peer pressure. @ rate, here question reproduced best of memory.
i think of confusion may have come distinction between object , collection of objects. possible solution, used class each function belong collection class.
the recursive function commented line-by-line, hope it's clear enough.
<?php class related_object { public $id; public $name; public $parentid; public function __construct($id, $name, $parent=0) { $this->id = $id; $this->name = $name; $this->parentid = $parent; } } class related_object_library { public $objects; public function add($object) { $this->objects []= $object; } public function addresspath($id, $path='') { // iterate through each object in collection foreach ($this->objects $object){ // if id matches, return name if ($object->id === $id) { $path = $object->name.$path; // if has parent, recurse, else return if (!empty($object->parentid)) return $this->addresspath($object->parentid,"->$path"); else return $path; } // end if match } // end loop } // end function } // end class $collection = new related_object_library(); $collection->add(new related_object(1,'egypt')); $collection->add(new related_object(2,'usa')); $collection->add(new related_object(3,'giza',1)); $collection->add(new related_object(4,'6th october',3)); echo $collection->addresspath(4); hopefully you're doing homework , researching subject, maybe you're lucky enough come across answer.
