Table of calculations

Control Statements example from a Well House Consultants training course
More on Control Statements [link]

This example is described in the following article(s):
• Predictions for the seagull population - [link]

If you're searching for a page where you can try this code, select here

This example references the following resources:
http://www.wellho.net/pix/gosportsb4.jpg
http://www.timesonline.co.uk/tol/news/uk/article622947.ece
http://www.wellho.net/pix/surnames.jpg
http://nz.answers.yahoo.com/question/index?qid=20080408163225AAsr4ZZ
http://www.wellho.net/course/php.html
http://wiki.answers.com/Q/What_is_the_life_span_of_a_seagull
http://wiki.answers.com/Q/How_heavy_are_Seagulls

Source code: bristolgulls.php Module: H104


<?php

/*  NOTE ... from PHP 5.1.0 ... supress timezone warnings:

Warning: date() [function.date]: It is not safe to rely on the
system's timezone settings. You are *required* to use the date.timezone
setting or the date_default_timezone_set() function. In case you used
any of those methods and you are still getting this warning, you
most likely misspelled the timezone identifier. We selected
'Europe/London' for 'BST/1.0/DST' instead in
/Library/WebServer/live_html/phpc/bristolgulls.php on line 4  */

date_default_timezone_set('Europe/London');

$startyear = 2006;
$endyear = date("Y") + 30;

$gulls = 4000;
$expand = 17;

$bristolians = floor(421300 / 1.014614 / 1.014614); # From 2008 -> 2006
$expand_b =  1.4614;

$table = "";

for ($year = $startyear; $year<=$endyear; $year++) {
        $table .= "<tr>";
        $table .= "<td>$year</td>";

        $bpg = sprintf("%.1f",$bristolians / $gulls);

        $table .= "<td>$gulls</td>";
        $gulls = floor($gulls * (1.0 + 0.01 * $expand));

        $table .= "<td>$bristolians</td>";
        $bristolians = floor($bristolians * (1.0 + 0.01 * $expand_b));

        $table .= "<td>$bpg</td>";

        $table .= "<tr>";
}
?>
<html>
<head>
<title>Predictions of growth of seagull population in Bristol</title>
</head>
<body>
<h1>Bristol Seagull Populations</h1>
<table><tr valign="top"><td>
<img src="http://www.wellho.net/pix/gosportsb4.jpg" align="left" hspace="5" />
<i>From "The Times Online", 30th August 2006 ... </i><br /><br />
Bristol City Council is hoping to save &pound;25,000 from its annual
budget by sacrificing the snacks from all of its meetings and hearings.
<br /><br />
Instead, the money will be spent on dipping seagull eggs in oil
so they do not hatch.
<br /><br />
The city is home to more than 2,000 pairs of the birds - and the
population is rising by an estimated 17 per cent per year. <a
href="http://www.timesonline.co.uk/tol/news/uk/article622947.ece">[more]</a>
<br clear="all" />
<hr />
<img src="http://www.wellho.net/pix/surnames.jpg" align="left" hspace="5" />
<i>From other research online ...</i><br /><br />
Human population [Bristol] rose from 380615 in 2001 to 421300 in 2008 -
a compound growth rate of 1.4614%<br />
<br />What does that mean about relative human and gull populations for
the next 30 years?<br /><br />
Could we eat seagulls?
<a href="http://nz.answers.yahoo.com/question/index?qid=20080408163225AAsr4ZZ">
[discussion]</a><br clear="all" /><hr />
The table on the right shows the populations of people and gulls in
2006, and how both would continue to grow on the trends that were
current at that point; I'm writing this as a
<a href="http://www.wellho.net/course/php.html">PHP training course example</a>
and I have not researched further the effect of oil dipping, nor any other
factors that may effect either gulls (lack of perches?) or humans (lack
of decent public transport systems?) into the future.<hr />
<i>Some more interesting things!</i>
<br /><br />
Seagulls can live for 40 or 50 years ...
<a href="http://wiki.answers.com/Q/What_is_the_life_span_of_a_seagull">[ref]</a>
<br /><br />
Seagulls weigh between 4 and 5 kgs ...
<a href="http://wiki.answers.com/Q/How_heavy_are_Seagulls">[ref]</a>
</td><td>
<table border="1" cellpadding="6">
<tr><th>Year</th><th>Gulls</th><th>People</th><th>Ratio</th></tr>
<?= $table ?></table>
</td></tr></table>
</body>
</html>

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