Page 215 - Beginning PHP 5.3

Chapter 8: Objects

Try It Out A Car that Moves
The following example shows how adding a few methods to a class can really start to make it useful.
Save the script as car_simulator.php in your document root folder, then run it in your Web

browser. Figure 8 - 2 shows the result.

< !DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Strict//EN”
“http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd” >
< html xmlns=”http://www.w3.org/1999/xhtml” xml:lang=”en” lang=”en” >
< head >
< title > A Simple Car Simulator < /title >
< link rel=”stylesheet” type=”text/css” href=”common.css” / >
< /head >
< body >
< h1 > A Simple Car Simulator < /h1 >

< ?php

class Car {
public $color;
public $manufacturer;
public $model;
private $_speed = 0;

public function accelerate() {
if ( $this- > _speed > = 100 ) return false;
$this- > _speed += 10;
return true;
}

public function brake() {
if ( $this- > _speed < = 0 ) return false;
$this- > _speed -= 10;
return true;
}

public function getSpeed() {
return $this- > _speed;
}

}

$myCar = new Car();
$myCar- > color = “red”;
$myCar- > manufacturer = “Volkswagen”;
$myCar- > model = “Beetle”;

echo “ < p > I’m driving a $myCar- > color $myCar- > manufacturer $myCar- > model. <
/
p > ”;

echo “ < p > Stepping on the gas... < br / > ”;

while ( $myCar- > accelerate() ) {
echo “Current speed: “ . $myCar- > getSpeed() . “ mph < br / > ”;
}
177

9/21/09 9:03:34 AM
c08.indd 177
c08.indd 177 9/21/09 9:03:34 AM