Notice: Undefined variable: products in C:\xampp\htdocs\shirts.php on line 18

<?php include("inc/products.php");?>

<?php 
$pageTitle = "Mike's Full Catalog Of Shirts";
$section = "shirts";
include('inc/header.php'); ?>

    <div class="section shirts page">

        <div class="wrapper">

            <h1> Mike&rsquo;s Full Catalog Of Shirts</h1>

            <ul class="products">
            <!--This will loop round the array elements inproducts and put them into 
            another variable called product then will execute the block of code
            for each individual product-->
                    <?php foreach($products as $test => $product) { 
                        //makes a lst item in php format
                            echo "<li>";
                        //mkae a link with php
                        //have to use single quotes as there are
                        //"" in the code
                            echo '<a href="/shirt.php?id=' . $test .'">';
                        //Make a img src in php
                                             //reference to the img attribute
                                            // in the array
                            echo '<img src="' . $product["img"] . '" alt="' . $product["name"] . '">';
                        // html code in php format
                            echo "<p>View Details</p>";
                        //closing html tags
                            echo "</a>";
                            echo "</li>";
                        }
                    ?>

                </ul>

        </div>

    </div>

<?php include('inc/footer.php'); ?>