There are a lot of differences, but the object is more powerfull.
Is in a way to avoid rewrite code, and clean the code.
Think you want to do some operations to numbers in an array:
To keep it simple, I suppose you already get the values from array or object.
<?
$item = array(
'name'=>'carrot',
'price'=>0.20,
'stock' => 15
);
?>
For example, in an shop context, you want to get the price befor buy, and update the stock.
<?
function getprice($item){
return $item['price'];
}
function substock($item,$units){
$item['stock'] = $item['stock'] - $units;
}
echo getprice($item);
echo "<br/>";
echo substock($item,"3");
?>
It will output something like:
0.20
12
That can be a way, but what can we do with the objects:
<?
class items{
var $name , $price, $stock;
function __construct($in_name, $in_price, $in_stock){
if (!empty($in_name)){$this->name = $in_name;}
if (!empty($in_price)){$this->price = $in_price;}
if (!empty($in_stock)){$this->stock = $in_stock;}
}
function getprice(){
return $this->price;
}
function substock($units){
$newstock = $this->stock - $units;
$this->stock = $newstock;
return $newstock;
}
}
$item = new items("carrot","0.20","15");
echo $item->getprice();
echo "<br/>";
echo $item->substock("3");
?>
It will output something like:
0.20
12
Till this point is not a prety much difference, is'n it?
But imagine you want to create a bigger thing. Just play around with it.
Now I want to load an item just with the name of the carrot.
Then changing the method construct to be able to create an objet with different inputs:
var $name , $price, $stock;
function __construct($in_name, $in_price=NULL, $in_stock=NULL){
$args = func_num_args();
if ($args == 1){
$this->name = $in_name;
$this->fromdb($in_name);
}else{
if (!empty($in_name)){$this->name = $in_name;}
if (!empty($in_price)){$this->price = $in_price;}
if (!empty($in_stock)){$this->stock = $in_stock;}
}
}
function fromdb($name){
$sql = "SELECT * FROM items WHERE name = '" . $name . "'";
//... here we bring from database the item and put in an array called $itemdb.I skip this part to do it shorter. If you want, ask about and I'll post this peace and the database objet.
$this -> price = $itemdb['price'];
$this -> stock = $itemdb['stock'];
}
function getprice(){
return $this->price;
}
function substock($units){
$newstock = $this->stock - $units;
$this->stock = $newstock;
return $newstock;
}
}
$item = new items("carrot");
echo $item->getprice();
echo "<br/>";
echo $item->substock("3");
?>
If the value in the database is same as the example before.It will output something like:
0.20
12
But from here you have infinite posibilities. Just play more.
Give a family item, and creating new methods.
<?
class items{
var $name , $price, $stock, $family;
function __construct($in_name, $in_price=NULL, $in_stock=NULL, $in_family=NULL){
$args = func_num_args();
if ($args == 1){
$this->name = $in_name;
$this->fromdb($in_name);
}else{
if (!empty($in_name)){$this->name = $in_name;}
if (!empty($in_price)){$this->price = $in_price;}
if (!empty($in_stock)){$this->stock = $in_stock;}
if (!empty($in_family)){$this->family = $in_family;}
}
}
function fromdb($name){
$sql = "SELECT * FROM items WHERE name = '" . $name . "'";
//... here we bring from database the item and put in an array called $itemdb. I skip this part to do it shorter. If you want, ask about and I'll post this peace and the database objet.
$this -> price = $itemdb['price'];
$this -> stock = $itemdb['stock'];
$this -> family = $itemdb['family'];
}
function getprice(){
return $this->price;
}
function getfamily(){
return $this->family;
}
function substock($units){
$newstock = $this->stock - $units;
$this->stock = $newstock;
return $newstock;
}
function veggiesinfamily(){
$sql = "SELECT count(name),family FROM items WHERE family = '" . $this->family . "'";
//... here we bring from database the number of item of a family product in $number. I skip this part to do it shorter. If you want, ask about and I'll post this peace and the database objet.
return $number;
}
function familystock(){
$sql = "SELECT SUM(stock),family FROM items WHERE family = '" . $this->family . "'";
//... here we bring from database the sum of stock items of a family product in $number. I skip this part to do it shorter. If you want, ask about and I'll post this peace and the database objet.
return $number;
}
}
$item = new items("carrot");
echo "There are " . $item->veggiesinfamily() . $item->getfamily() . " kinds.<br/>";
echo "There are " . $item->familystock() . " units of " . $item->getfamily();
?>
We have also in our database an item: potato, 0.3, 10, roots (name, price, stock, family)
If the value in the database have as family roots and as elements carrot and potatoe. The output will be.
There is 2 roots kinds.
There is 25 units of roots.
And so on.
If you load the objet from an external file as item_class.php, and load as include("item_class.php"), can grow your script easily.
Cheers.
