Just archiving this project from my Open Source Software class.

config/cart.php

@@ -0,0 +1,51 @@
+<?php
+// Add an item to the cart
+function add_item($key, $quantity) {
+    global $products;
+    if ($quantity < 1) return;
+
+    // If item already exists in cart, update quantity
+    if (isset($_SESSION['cart12'][$key])) {
+        $quantity += $_SESSION['cart12'][$key]['qty'];
+        update_item($key, $quantity);
+        return;
+    }
+
+    // Add item
+    $cost = $products[$key]['cost'];
+    $total = $cost * $quantity;
+    $item = array(
+        'name' => $products[$key]['name'],
+        'cost' => $cost,
+        'qty'  => $quantity,
+        'total' => $total
+    );
+    $_SESSION['cart12'][$key] = $item;
+}
+
+// Update an item in the cart
+function update_item($key, $quantity) {
+    global $products;
+    $quantity = (int) $quantity;
+    if (isset($_SESSION['cart12'][$key])) {
+        if ($quantity <= 0) {
+            unset($_SESSION['cart12'][$key]);
+        } else {
+            $_SESSION['cart12'][$key]['qty'] = $quantity;
+            $total = $_SESSION['cart12'][$key]['cost'] *
+                     $_SESSION['cart12'][$key]['qty'];
+            $_SESSION['cart12'][$key]['total'] = $total;
+        }
+    }
+}
+
+// Get cart subtotal
+function get_subtotal() {
+    $subtotal = 0;
+    foreach ($_SESSION['cart12'] as $item) {
+        $subtotal += $item['total'];
+    }
+    $subtotal = number_format($subtotal, 2);
+    return $subtotal;
+}
+?>

config/db.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * Configuration file for: Database Connection
+ * This is the place where your database login constants are saved
+ *
+ * For more info about constants please @see http://php.net/manual/en/function.define.php
+ * If you want to know why we use "define" instead of "const" @see http://stackoverflow.com/q/2447791/1114320
+ */
+
+
+/**
+ * database host, usually it's "127.0.0.1" or "localhost", some servers also need port info, like "127.0.0.1:8080"
+ */
+define("DB_HOST", "localhost");
+
+/**
+ * name of the database. please note: database and database table are not the same thing!
+ */
+define("DB_NAME", "login");
+
+/**
+ * user for your database. the user needs to have rights for SELECT, UPDATE, DELETE and INSERT.
+ * by the way, it's bad style to use "root". In a real application you should create a database user
+ * that fits your needs.
+ */
+define("DB_USER", "root");
+
+/**
+ * The password of the above user
+ */
+define("DB_PASS", "");