php OO programming help

[Anon]

Hey everyone,

I am trying to learn how to use classes in php but I am having a little bit of trouble, can any one take a look at this code and tell me why it only prints "make" when I try to view it?

<?php

class vehicle {
var $make;
var $model;
var $year;
var $color;
var $miles;
var $condition;

function view_car() {
echo("$year &nbsp; $make &nbsp; $model<br>$miles miles &nbsp; $condition<br>");
}

}

$myCar = new vehicle();
$myCar->make = "Ford";
$myCar->model = "Bronco II";
$myCar->year = "1984";
$myCar->color = "Black";
$myCar->miles = "77, 500";
$myCar->condition = "Great";
$myCar->view_car();
?>

Thanks,

Ben

[wombatee]

Because the variables you've created are properties of the object (a slightly different concept than regular variables), you need to refer to them in an object context.

The "this" keyword is what you're looking for:

echo("$this->year $this->make $this->model<br>$this->miles miles $this->condition<br>");

'this' refers to the specific instance of the object that you're working with. So if you've created a vehicle A using

$A = new vehicle();

then when $A->view_car() is called, the 'this' keyword accesses that specific object's properties (in this case, A's properties).

Good luck!

Omega Wombat
http://www.drinknation.com

[Anon]

<?
class vehicle {
var $make;
var $model;
var $year;
var $color;
var $miles;
var $condition;

function view_car() {
echo("Make: $this->make<br>
Model: $this->model<br>
Year: $this->year<br>
Color: $this->color<br>
Miles: $this->miles<br>
Condition: $this->condition");
}
}

$car = new vehicle();
$car->make = "Ford";
$car->model = "Bronco II";
$car->year = "1984";
$car->color = "Black";
$car->miles = "77, 500";
$car->condition = "Great";
$car->view_car();
?>

[Anon]

You can also make a constructor and send the values in there (i think it looks better that way...):

<?
class vehicle {

var $make;
var $model;
var $year;
var $color;
var $miles;
var $condition;

function vehicle($make, $model, $year, $color, $miles, $condition) {
$this->make = $make;
$this->model = $model;
$this->year = $year;
$this->color = $color;
$this->miles = $miles;
$this->condition = $condition;
}

function view_car() {
echo("<table border=0>
<tr><td>Make:</td><td>$this->make</td></tr>
<tr><td>Model:</td><td>$this->model</td></tr>
<tr><td>Year:</td><td>$this->year</td></tr>
<tr><td>Color:</td><td>$this->color</td></tr>
<tr><td>Miles:</td><td>$this->miles</td></tr>
<tr><td>Condition:</td><td>$this->condition</td></tr></table>");
}

}

$car = new vehicle("Ford", "Bronco II", "1984", "Black", "77, 500", "Great");
$car->view_car();

// some months later;

echo "<br><br>";

$car->miles = "97, 500";
$car->condition = "Lots and lots of scratches!";

$car->view_car();
?>