CODEWITHSUNDEEP
phpclassobjectproperties
Patricia LaVish
Patricia LaVish

Reputation: 1

Objects and properties

This is homework. I must say that the instructions are not very clear, but this is what I've "deciphered". I must create 1 class with 1 "subclass" in different files. Parent class is:

<?php
class Objecte
{
var $model;
private $preu;

public function __construct($model,$preu)
{   
    $this->model=$model;
    $this->preu=$preu;  
}
}
?>

The "subclass" is:

<?php
include('classe_objecte.php');
class Ordinador extends Objecte
{
private $disc_dur;
private $ram;

public function Ordinador($model,$preu,$disc_dur,$ram)
{
    parent::__construct($model,$preu);
    $this->disc_dur=$disc_dur;
    $this->ram=$ram;    
}   
}
?>

I must create an "ordinador" object with properties $model,$preu,$disc_dur,$ram to show them later. This information comes from an HTML form that sends it via $_POST to a file called "ordinadors.php". As I'll have more than 1 object, I want the object name to be a variable variable. The name will be the word "ordinador" and a number provided in a session variable called 'numOrdinadorsO'. This is part of the "ordinadors.php" code:

include_once('classe_ordinador.php');
/*some other code here*/
$name="ordinador".$_SESSION['numOrdinadorsO'];
$$name=new Ordinador($model,$preu,$disc_dur,$ram);

If I var_dump($$name), I get this:

object(Ordinador)#1 (4) { ["disc_dur":"Ordinador":private]=> string(3) "100" ["ram":"Ordinador":private]=> string(1) "8" ["model"]=> string(7) "modelo1" ["preu":"Objecte":private]=> string(3) "200" }

After creating the object, I must search for an specific "model" and return the other attributes related to that model (preu, ram, etc.). And there problems start. This is the code:

function consultarOrdinadorO()
{   
    $model_buscat=$_POST['ordinador_busqueda'];
    $valor=$_SESSION['numOrdinadorsO'];
    $contador=0;
    $trobat=false;
    do 
    {
        for ($i=0; $i<$valor; $i=$i+1)
        {
            $name="ordinador".$i;
            if ($$name->model==$model_buscat)  <-- this is line 91
            {
                echo "Model $model_buscat trobat.";
                $trobat=true;
                break;
            } else {
                $contador+=1;
            }
        }
    }
        while ($trobat==false && $contador<$valor);

    if ($trobat==false)
    {
        echo "Model $model_buscat no trobat.";
    }       
}

I get this error (I have insered information of 3 "ordinadors" before):

Notice: Undefined variable: ordinador0 in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Notice: Trying to get property of non-object in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Notice: Undefined variable: ordinador1 in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Notice: Trying to get property of non-object in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Notice: Undefined variable: ordinador2 in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Notice: Trying to get property of non-object in C:\Users\Quenya\IOC\2014-2015\S2\M09 PHP\EAC1\Ejercicios\Exercici2\ordinadors.php on line 91

Any help?. I've looked in the forums for other questions like this but I haven't found any. I guess I'm probably not understanding well how objects and classes work, but the information provided by the teacher is... very limited.

Thanks a lot!.

UPDATE 1: Thanks u_mulder, I think I'm seeing some light now. But... I keep having some problems :-(.

Additional information I missed before: I have an HTML form with 2 buttons. - Button "inserir": I insert the ordinador information. Button "consultar": I insert a model in a text box, and I click the model so it searches the model.

Code in ordinadors.php to specify which funtion call when I click one button or the other:

session_start();
include_once('classe_ordinador.php');
$objetos=arrray();

//some other code here

if (isset($_POST['inserir'])) 
{
    inserirOrdinador();
    inserirOrdinadorS();        
    inserirOrdinadorO();
    var_dump($objetos);
} elseif (isset($_GET['consultar'])=='consultar')
{
    consultarOrdinador();
} elseif (isset($_POST['consultar_ordinador']))
{   
    if (empty($_POST['ordinador_busqueda']))
    {
        echo "Model no introduit.";
    }else
    {

        var_dump($objetos);
        /*
        consultarOrdinadorS();
        consultarOrdinadorO($objetos);
        */
    }
}

inserirOrdinadorO now looks like this:

function inserirOrdinadorO()
{
      $_SESSION['ordinadorsO']=array('model_ordinadors'=>$_POST['model_ordinadors'],'preu_ordinadors'=>$_POST['preu_ordinadors'],'tamany'=>$_POST['tamany'],'ram'=>$_POST['ram']);

    $model=$_SESSION['ordinadorsO']['model_ordinadors'];
    $preu=$_SESSION['ordinadorsO']['preu_ordinadors'];
    $disc_dur=$_SESSION['ordinadorsO']['tamany'];
    $ram=$_SESSION['ordinadorsO']['ram'];

    global $objetos;
    $obj_id = $_SESSION['numOrdinadorsO'];
    $ord_tmp = new Ordinador($model,$preu,$disc_dur,$ram);
    $objetos[$obj_id] = $ord_tmp;

    $_SESSION['numOrdinadorsO']+=1;
    echo "Objecte Ordinador inserit.</br>";
}

So the var_dump($objetos) here is showing me the values I added in inserirOrdinadorO:

if (isset($_POST['inserir'])) 
{
    inserirOrdinador();
    inserirOrdinadorS();        
    inserirOrdinadorO();
    var_dump($objetos);

but the one here 

} elseif (isset($_POST['consultar_ordinador']))
{   
    if (empty($_POST['ordinador_busqueda']))
    {
        echo "Model no introduit.";
    }else
    {

        var_dump($objetos);

returns this:

array(0) { }

I guess that it's because it's reading $objetos here and of course it's empty:

session_start();
include_once('classe_ordinador.php');
$objetos=array();

But... how do I make it so I can read it from there too?.

Sorry, I'm just begining with php. I read the link you sent but I think I'm missing the point here :-(

Thanks a lot for your help.

Upvotes: 0

Views: 54

Answers (1)

u_mulder
u_mulder

Reputation: 54841

First, when you have a bunch of similar objects and you need to store them - use array. So, when you have some session value:

$obj_id = $_SESSION['numOrdinadorsO'];
// instead of using variable variables use arrays:
$objects = array();  // array to store your objects
$ord_tmp = new Ordinador($model,$preu,$disc_dur,$ram);
// Now you have all your objects of type Ordinador in an array
$objects[$obj_id] = $ord_tmp;

Your main problem is function scope. When you call for consultarOrdinadorO, this function works in it's own scope, so it doesn't know about any outer variables. There are two ways of solving this:

In your current function, before you try to access $$name you should declare it as global, so that function know that this variable is defined somewhere else:

for ($i=0; $i<$valor; $i=$i+1)
{
    $name="ordinador".$i;
    // add the following line
    global $$name;
    // other code is the same

Or you can pass your variables as arguments. But in your case you don't know how many objects do you have. That's why I advise you to use arrays. After you get all Ordinators to array you can define your function as:

function consultarOrdinadorO($ordinators) 
{
    // code skipped
    for ($i=0; $i<$valor; $i=$i+1)
    {
        $cur_obj = $ordinators[$i];
        if ($cur_obj->model ==  )
    // code skipped
}

Assuming you collect all your objects earlier to $objects array, function call will be consultarOrdinadorO($objects)

More about functions here: https://www.php.net/language.functions.php

Upvotes: 1

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