echo "<h1>MPG Calculator</h1>";
echo "<h2>This relates to Imperial quantities - that is, this works for UK visitors.</h2>";
echo "<P>If you use US Gallons, the calclations will be incorrect. If you would like this";
echo " feature to allow the option of US Gallons, please <a href=\"/mail/\">mail me</a> and I will add that option. However, the &quot;Pence Per Litre&quot; option should work for all decimal (xx.xx) currencies.";
";

if (isset($_POST["calc"])) {
  echo "<table border=1>";
  echo "<tr><th>Litres</th><td>" . $_POST["litres"] . "</td></tr>";
  $g=$_POST["litres"] * 0.22;
  $mpg=$_POST["miles"] / $g;
  printf("<tr><th>Gallons</th><td>%0.2f</td></tr>", $g);
  printf("<tr><th>MPG</th><td>%0.2f</td></tr>", $mpg);
  echo "</table>";
  printf("<p>%0.2f miles fuelled by %0.2f litres equates to <strong>%0.2f MPG</strong></P>", $_POST["miles"], $_POST["litres"], $mpg);
  $cost = $_POST["ppl"] * $_POST["litres"] / $_POST["miles"];
  printf("<P>Cost per Mile at %0.2f pence per litre = <strong>%0.2f pence per mile</strong></P>", $_POST["ppl"], $cost);
}
  echo "<table border=1>";
  echo "<form action=\"mpg.php\" method=post>"; 
  echo "<tr><th>Litres</th><td><input type=text value=\"" . $_POST["litres"] . "\" name=litres size=4></td><td class=descr>How many Litres you put into the car</td></tr>";
  echo "<tr><th>Miles</th><td><input type=text value=\"" . $_POST["miles"] . "\" name=miles size=4></td><td class=descr>How many Miles the car drove</td></tr>";
  echo "<tr><th>Pence Per Litre</th><td><input type=text value=\"" . $_POST["ppl"] . "\" name=ppl size=4></td><td class=descr>How many pence you paid per litre at the pump</td></tr>";
  echo "</table>";
  echo "<input type=submit name=calc value=\"Calculate MPG and Costs\">";
  echo "</form>";