Looping PHP Numbers To Make A Slideshow - php

Question

I have this page that looks a little like this.
<div class="ecigcontainer">
<div class="backbutt"><?php include("php/back.php"); ?></div>
<div class="ecig"><?php include("php/ecig.php"); ?></div>
<div class="forwardbutt"><?php include("php/forward.php"); ?></div>
</div>
A back button that works like this.
<?php
if (isset($_GET["ecig"])) {
$back = $_GET["ecig"] - 1;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";
} else {
$back = $_GET["ecig"] - 1;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";
}?>
The forward button pretty much has the same code, and the display looks like this.
<div class="ecigpic">
<img src="images/ecigs/<?php include("php/ecigcounter.php"); ?>.png" height="400px" />
</div>
<div class="ecigdesc">
<?php
if (isset($_GET["ecig"])) {
include("ecigs/" . $_GET["ecig"] . ".php");
echo "<h3>" . $ecigname . "</h3>";
echo "<p>" . $ecigdesc . "</p>";
} else {
$_GET["ecig"] = 1;
include("ecigs/" . $_GET["ecig"] . ".php");
echo "<h3>" . $ecigname . "</h3>";
echo "<p>" . $ecigdesc . "</p>";
}?>
</div>
With the "ecigcounter" that does this.
<?php
if (isset($_GET["ecig"])) {
echo $_GET["ecig"];
} else {
$_GET["ecig"] = 1;
echo $_GET["ecig"];
}?>
But the whole reason for this question is, how to I make it so it only displays numbers 1-40? Kind of lost and can't really seem to figure it out, and put it where it needs to go.

Answer 1

All the it needed was
<?php
if (isset($_GET["ecig"])) {
if ($_GET["ecig"] == 1){
$back = 40;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";
} else {
$back = $_GET["ecig"] - 1;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";
}
} else {
$back = $_GET["ecig"] - 1;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";
}?>
This little script made the world.
if ($_GET["ecig"] == 1){
$back = 40;
echo "<a href=\"?ecig=" . $back . "\">";
echo "<img src=\"images/ecigs/" . $back . ".png\" height=\"300px\" /></a>";