Question

I’m experimenting with classes and objects for the first time and I thought I’d make a template for a Box that can store things like Books. (Thinking in terms of real-world items)

<?php

function feetToInches($feet){
    $feet = $feet * 12;
    return $feet;
}



class Book{
    var $l = 6;
    var $w = 5;
    var $h = 1;
}

class Box{
    //This is a box. It has length, width, and height, and you can put things in it.
    var $length = 0;
    var $width = 0;
    var $height = 0;
    var $storedArray = array();

    function setDimensions($l, $w, $h){
        $this->length = feetToInches($l);
        $this->width = feetToInches($w);
        $this->height = feetToInches($h);
    }


    function storeThings($thing){
        $this->storedArray[] = $thing;
    }

    function getThings(){
       return $this->storedArray;
    }

}



$thatBook = new Book;
$BookBox = new Box;


$BookBox->setDimensions(6,5,1);


for($i = 0; $i < 5; $i++){
    $BookBox->storeThings($thatBook);
}


echo $BookBox->getThings() . "<br />";

/*
foreach($BookBox->getThings() as $item){
echo $item;
}
*/


var_dump($BookBox);

?>

So what I have is simple here, you have boxes of a dimension, and you throw books of a fixed dimension in them.

Putting things in it is no problem, but when I try to retrieve them, I either get errors or nothing happens. And when I try to specify a key for the array like

echo $BookBox->getThings()[2];

I get an error that it’s not an array or something.

So can someone please point me in the right direction here?

And normally the class would be a separate file, but I’m just learning here.

Answer 1

First, you cannot do echo since what you’ll get is not a string but an object. Use print_r() or var_dump() instead.

Second, just like the other answers here, you should do this.

$books = $BookBox->getThings();
print_r($books[2]);

But I suggest you to make getThings() accept a variable for getting a specified array element:

function getThings($key = null) {
  if ($key) {
    return isset($this->storedArray[$key]) ? $this->storedArray[$key] : null;
  } else {
    return $this->storedArray;
  }
}

// Then you can do this
// print_r($BookBox->getThings(2));