Page 104 - Beginning PHP 5.3
P. 104
Part II: Learning the Language
Incidentally, you can also use a numeric argument with break in this way to break out of nested switch
constructs (or, for example, a switch embedded within a while or for loop).
Try It Out A Homing Pigeon Simulator
Here’s an example script that brings together some of the concepts you’ve learned in this chapter so
far. The script graphically simulates the path of a homing pigeon as it flies from its starting point to its
home. We’re not exactly talking 3-dimensional animated graphics here, but it gets the idea across!
Here’s the script in all its glory:
<!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>Homing Pigeon Simulator</title>
<link rel=”stylesheet” type=”text/css” href=”common.css” />
<style type=”text/css”>
div.map { float: left; text-align: center; border: 1px solid #666;
background-color: #fcfcfc; margin: 5px; padding: 1em; }
span.home, span.pigeon { font-weight: bold; }
span.empty { color: #666; }
</style>
</head>
<body>
<?php
$mapSize = 10;
// Position the home and the pigeon
do {
$homeX = rand ( 0, $mapSize-1 );
$homeY = rand ( 0, $mapSize-1 );
$pigeonX = rand ( 0, $mapSize-1 );
$pigeonY = rand ( 0, $mapSize-1 );
} while ( ( abs( $homeX - $pigeonX ) < $mapSize/2 ) && ( abs( $homeY -
$pigeonY ) < $mapSize/2 ) );
do {
// Move the pigeon closer to home
if ( $pigeonX < $homeX )
$pigeonX++;
elseif ( $pigeonX > $homeX )
$pigeonX--;
if ( $pigeonY < $homeY )
$pigeonY++;
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