OOP

[justinh]

Okay I'm trying to get a grasp on OOP

 

The book I am reading is "PHP and MySQL Web Development" Third Edition.

 

Here's what i got so far..

<?php include("class_lib.php");

$a = new classname('First');
$b = new classname('Second');
$c = new classname('Third');

?>

 

 

class_lib.php

 
<?php

class classname
{

function __construct($param){

   echo "Constructor called with parameter $param <br />" ;
   
   }
   
}
   

 

 

But, nothing is being outputted.

 

What am I doing wrong? =( 

[premiso]

Are you working on a PHP5 or PHP4 server?

 

If 4, change __construct to classname and it should work.

 

 

[justinh]

sweet. thanks for the help buddy

[justinh]

as it stands now.. it seems like OOP will take a little while to fully understand.. =/

 

but i wont give up.

[premiso]

as it stands now.. it seems like OOP will take a little while to fully understand.. =/

 

but i wont give up.

 

PHP4 is bad to try programming in OOP in, I would try and do it on a PHP 5 server. Since PHP4 OOP will be outdated once most servers are 5, it is better to code for the future, not the past. Plus PHP5 handles OOP a ton better than 4 does.

[Mchl]

as it stands now.. it seems like OOP will take a little while to fully understand.. =/

 

but i wont give up.

 

Not to worry you, but it took me 7 years just to understand why it might be useful

 

As premiso said, move to PHP5 asap. OOP in PHP4 is not OOP. It just mimicks some OOP-like behaviours.

[justinh]

Okay i upgraded to PHP5

 

I'm starting to "Kind of" understand OOP.

 

Here is something i wrote,

 

<?php

class classname

{
var $total;
function __construct($x,$y) {

  
  $this->total = $x*$y;
  echo $x." times ".$y." equals ".$this->total."<br />";
  }
  
}


$a = new classname('5','2');
$b = new classname('10','3');

?>

 

 

I know its pretty beginner stuff.. but im excited lol

[CroNiX]

A few suggestions...  I'm not a pro PHP OOP guy, so take it with a grain of salt, but this is what I have learned.

class classname
{
private $total;  // using var is outdated (php4 style) look in to public, private, etc. variables
public $var1;
public $var2;

function __construct($x,$y) {
  $this->total = $x*$y;
  $this->var1 = $x;
  $this->var2 = $y;
}
public function getTotal(){
//you should do the same thing with declaring methods, use public, private, static etc.
//its also not a good idea to echo from a class, you should return the data so you can format it in your code and keep a separation of HTML and Data.
   return $this->total;
}
}
$a = new classname('5','2');
$b = new classname('10','3');

//now you have more control on how you format your data via html
echo $a->var1 . ' times ' . $a->var2 . ' equals ' . $a->getTotal() . '<br />';
echo $b->var1 . ' x ' . $b->var2 . ' = ' . $b->getTotal() . '<br />';

[justinh]

okay i took your advice and heres what i came up with

 

class_lib.php

<?php
class process {

public $x;
public $y;


    public function add(){
    
       return $this->x + $this->y;
       
       }
    public function subtract(){
    
       return $this->x - $this->y;
    
       }
       
    public function multiply(){
    
    return $this->x * $this->y;
    
    
    
       }
       
    public function divide(){
    
    return $this->x / $this->y;
    

       }
       
    
       


}
?>

 

 

index.php

<?php
                                   
include("class_lib.php");




$add = new process();

$add->x = 10;
$add->y = 11;

echo $add->x." minus ".$add->y." equals ".$add->subtract()."<br />";
echo $add->x." times ".$add-y." equals ".$add->multiply()."<br />";
echo $add->x." plus ".$add-y." equals ".$add->add()."<br />";
echo $add->x." divided by ".$add-y." equals ".$add->divide()."<br />";



?>

 

This gives me an eror of :

 

Catchable fatal error: Object of class process could not be converted to string in /homepages/29/d119570661/htdocs/wmptest.com/ooptraining/index.php on line 14

 

 

 

[CroNiX]

You are missing a ">" in this line:

echo $add->x." divided by ".$add-y." equals ".$add->divide()."<br />";

[justinh]

ahh okay, yet another dumb mistake by me.