Question

I am a beginner at programming. I am writing code using class inheritance. Here is the full code:

require_once('db.php');
class Activity extends DatabaseCall //this is in db.php
{ 

    public $name, $link, $activity_id;

    public function oneActivity( $name, $link, $activity_id )
    {
        $this->name = $name;
        $this->link = $link;
        $this->activity_id = $activity_id;
    } 
    private function activitiesArrays()
    {
        $this->sqlActivities(); //a protected function inherited from Parent
    }

    //Returns array of name + link + activity_id for random activity.
    //Works with function activitiesArrays(), which returns An Array of arrays of
    //names,links,and id's.
    // @param <array> $namesLinksIds_Arrays An Array of arrays of names, links,and  
    //id's.
    public function makesRandomActivity($namesLinksIds_Arrays)
    {
     $list($name, $linkk, $id) = $namesLinksIds_Arrays;
     $length = count($name);
     $rand = rand(0, $length-1);
        $n = $name[$rand];
        $l = $linkk[$rand];
        $i = $id[$rand];
     oneActivity($n, $l, $i);
    }

}

Everything in this code works if I comment out this code:

 public function makesRandomActivity($namesLinksIds_Arrays)
{
 $list($name, $linkk, $id) = $namesLinksIds_Arrays;
 $length = count($name);
 $rand = rand(0, $length-1);
    $n = $name[$rand];
    $l = $linkk[$rand];
    $i = $id[$rand];
 oneActivity($n, $l, $i);
}

Please help me figure out why this code does not work. Any help/suggestions/tips appreciated.

Answer 1

The following line is incorrect :

$list($name, $linkk, $id) = $namesLinksIds_Arrays;

You want to use the list() language construct — so, remove the $ :

list($name, $linkk, $id) = $namesLinksIds_Arrays;

Using what you did, PHP intepreted the $list(...) as calling a function which name would have been contained inside the (unexisting) $link variable — about that, see Variable functions.

Which basically means you were trying to assign $namesLinksIds_Arrays to a function invokation — which is why you were getting the following error message :

Fatal error: Can't use function return value in write context