OOP Related Question

[makeshift_theory]

Ok, I've recently got addicted to the OOP part of PHP, and I have a question reguarding to the inheirtance featured in PHP.  From what I've read you can only extend to one class however if you chain them all of the properties from a ancestor class should be present in the child class.  For example:
[code]
Class example1
{
    public var $home = "new home";
    function __constructor($text)
    {
        $this->home = "$test";
    }
}
Class example2 extends example1
{
    public var $ex2 = "ex2";
}
Class example3 extends example2
{
    public var $ex3 = "ex3";
}
Class example4 extends example3
{
    function print_stuff()
    {
      echo $this->home;
      echo $this->ex2;
      echo $this->ex3;
      return true;
    }
}
$ex = new example("This is a test");
$ex4 = new example4;
$ex4->print_stuff();
Result
------------------
"This is a test" "ex2" "ex3"
[/code]

Is this about right?  If so then I can ask my next question, however I want to make sure my understanding is correct first, thanks.

[trq]

[quote]Is this about right?[/quote]

Yes.

[makeshift_theory]

Ok well with that being said, here is the code I have to inquire about:
[code]
class stats extends login
{
/*
Gathers all stats relevant to character
*/
var $int; // Intelligence
var $str; // Strength
var $agi; // Agility
var $wis; // Wisdom
var $def; // Defense
static $sta; // Stamina
var $hp; // HP
var $mp; // MP
var $clvl; // character level

function gather_stats()
{ // Gathers stats based on the login classes id
$this->update_session();
$this->db_query("SELECT * FROM char_stats where c_id = '$this->chosen_char' and a_id = '$this->id'"); // Get specific character information
$result = $this->db_readall();
list($blank,$blank,$blank,$this->hp,$this->mp,$this->wis,$this->agi,$this->int,$this->str,$this->def,$this->sta,$this->clvl) = $result; // Assign Results
$blank=''; // clear our blank container since list always starts with the 0 iterator
$_SESSION['clvl'] = $this->clvl; // Register Character Level
return true;
}


}
class draw_items extends stats
{ // Draws all needed items to screen.

function draw_login()
{ // Draws Login fields to screen for use
$login = "<form action=" . $_SERVER['PHP_SELF'] . " method='POST'>";
$login .= '<table width="45%" cellspacing="0" cellpadding="0" border="0">';
$login .= '<tr>';
$login .= '<td>';
$login .= 'E-mail: ';
$login .= '</td>';
$login .= '<td>';
$login .= '<input type="text" name="username">';
$login .= '</td>';
$login .= '</tr>';
$login .= '<tr>';
$login .= '<td>';
$login .= 'Password: ';
$login .= '</td>';
$login .= '<td>';
$login .= '<input type="password" name="password">';
$login .= '</td>';
$login .= '</tr>';
$login .= '<tr>';
$login .= '<td align="right" colspan="2">';
$login .= '<input type="submit" value="Login" name="submit">';
$login .= '</td>';
$login .= '</tr>';
$login .= '</form>';
echo $login;
return true;
}
}
class char_select extends draw_items
{ // Handles the character select menu

const total_chars = 3; // Total number of allowed characters
var $players_chars; // Number of players characters that he or she currently has
var $chosen_char; // Stores chosen characters id

function get_char_list()
{ // This will connect to database get a list of all of the person's characters and display them so the player can choose a character to play with
$this->db_query("SELECT * FROM char_table WHERE a_id = '$this->id'"); // This query will find all characters associated with the login account number
$this->players_chars = mysql_num_rows($this->queryr); // Assigns number of players characters
$this->draw_char_menu(); // Draws the character menu
return true;
}
private function draw_char_menu()
{
if($_SERVER['REQUEST_METHOD']=='POST')
{
extract($_POST);
foreach($_POST as $k => $v)
$key_c = $k;
$_SESSION['cid'] = $key_c; // Set Session Character ID
$this->chosen_char = $_SESSION['cid']; // Set character id
include "js/opengame.js"; // Open and Start Game
}
else
{
$char_table = "<form action=". $_SERVER['PHP_SELF'] ." name='charform' method='POST'>";
$char_table .= '<table width="650" cellspacing="0" cellpadding="0" border="0" align="center">';
$char_table .= '<tr>';
while($r = mysql_fetch_array($this->queryr))
{
$char_table .= '<td width="200" valign="top">';
$char_table .= '<table width="200" height="400" cellspacing="0" cellpadding="0" border="1" align="center">';
$char_table .= '<tr>';
$char_table .= '<td height="25" valign="middle" align="center">';
$char_table .= $r[4] . " " . $r[3];
$char_table .= '</td>';
$char_table .= '</tr>';
$char_table .= '<tr>';
$char_table .= '<td align="center" valign="middle">';
if($r[5] == "") // If the picture is null then use default
$r[5] = "images/portraits/default.jpg";
$char_table .= '<img src="'.$r[5].'" border="0" alt="'.$r[3].'\'s Portrait">';
$char_table .= '</td>';
$char_table .= '</tr>';
$char_table .= '<tr>';
$char_table .= '<td height="25" valign="middle" align="center">';
$char_table .= '<input style="width:200px" type="submit" value="Play This Character" name="'.$r[0].'">';
$char_table .= '</td>';
$char_table .= '</tr>';
$char_table .= ' </table>';
$char_table .= '</td>';
}
$char_table .= '</tr>';
$char_table .= '</table>';
$char_table .= "</form>";

echo $char_table;
return true;
}


}
}
class monster extends char_select
{ // Does Monster Related Things

var $mint; // Intelligence
var $mstr; // Strength
var $magi; // Agility
var $mwis; // Wisdom
var $mdef; // Defense
var $msta; // Stamina
var $mhp; // HP
var $mmp; // MP
var $mimg; // M image
var $mlvl; //M lvl
var $mname; // M Name'
var $mdrop; // Monster Drop List
var $malive; // If monster is not dead stay to 1
var $mmid; // Monster ID
var $mmlvl; // For Storeing Monster Level


function get_monster()
{ // Gets a random monster based on character level
$this->update_session(); // Updates Variables
$mid = array(); // init array
echo $this->clvl;
---->$this->mlvl = rand($this->clvl,2); // Produces a random number between characters lvl + 5
$this->db_query("SELECT * FROM mon_table WHERE mon_lvl = '$this->mlvl'"); // Compiles a list of all same lvl monsters

while($r = mysql_fetch_array($this->queryr))
$mid[] = $r[0]; // Compiles a list of all monster Id's

$nummonsters = count($mid);  // nummonsters is equal to the total number of monsters the query located
$randommonster = rand(0,($nummonsters - 1)); // Produces random monster integer

if($this->malive == 1)
{// Checks for refresh cheat, so they can't switch monsters by hitting refresh
$chosen_mon = $this->mmid;
$chosen_mlvl = $this->mmlvl;
}
else
{
$chosen_mon = $mid[$randommonster];
$chosen_mlvl = $this->mlvl;
}


$this->db_query("SELECT * FROM mon_table WHERE mon_lvl = '$chosen_mlvl' and mon_id = '".$chosen_mon."'"); // Will produce the random monster
$results = $this->db_readall();

list($this->mmid,$this->mlvl,$this->mhp,$this->mmp,$this->mstr,$this->mint,$this->magi,$this->msta,$this->mdef,$this->mname,$this->mimg,$this->mdrop) = $results; // Assign variables
$this->malive = 1; // Monster is active NO SWITCHING! and NO REFRESHING WILL SAVE YOU
$_SESSION['malive'] = 1; // Set Session Variable
$_SESSION['mmid'] = $this->mmid;
$_SESSION['mmlvl'] = $this->mlvl;
return true;

}
function draw_monster()
{ // Ouputs the imagegry for monster
$buffer = '<img src="images/monsters/'.$this->mimg.'" alt="'.$this->mname.'" border="0" >';
echo $buffer;

}

}
[/code]

I have declared my classes in the page like so:
$monster = new monster;
$stats = new stats;

My question is when I run my page, I do not get a value for $this->clvl in the monster class.  Although with inheirtance I should.  To fix the problem in the stat class I assign clvl to a Session and then I have a method that updates sessions which is why "$this->update_session(); // Updates Variables"  is the first like in the getmonster method.  Shouldn't I be able to get the value of $this->clvl without have to store it as a session is my question.

[trq]

Actually No. I didn't really look at your implimentation.

Setting a property on the fly within the construct of example1 will never show up in example4. youve got to rememebr that when you instantiate an object ($obj = new obj()) it is its own instance.

So, in your example $ex and $ex4 are two completely different objects.

And in fact, when you instantiate a child class, its parents construct is not called automatically. You'd need to call it manually within each child.

[makeshift_theory]

Okay now that makes a lot of sense, so to clarify and correct me if I'm wrong please.  Since I stored monster as a new object seperate from stats, monster has no idea what the new stats are.  In my program I use $stat->get_stats() so all of the stats get updated however since I'm using $monster as a second instance it has no knowledge of the new stats, is this correct?

EDIT: PS> Thanks thorpe for the quick responses, your awesome.

[trq]

[quote]since I'm using $monster as a second instance it has no knowledge of the new stats, is this correct?[/quote]

Yes. That is correct.

[makeshift_theory]

Okay, thanks again for the punctional responses.