Project: Shopping cart

PHP course · Beginner · Lesson 48/116

Overview of the 5-lesson shopping cart project: store products in an array and compute totals.

Project: Shopping cart

In this 5-lesson project you'll build a shopping cart. Each lesson adds one piece, and by the final lesson you'll have a complete working app.

You'll use what you learned before:

output with echo
variable assignment
looping with foreach
arithmetic operators

You'll also learn to store multiple products in a single variable using an array. Ready? Let's start.

Arrays and associative arrays

An array is a way to hold many values in a single variable. An empty array is created with $cart = []; a new element is appended with $cart[] = ....

When a product has several properties (name, price, quantity) you use an associative array. Keys and values are paired with =>: ["name" => "Pen", "price" => 25, "quantity" => 2]. You reach a property with $product["name"].

Exercise Add the first product to the cart

In this lesson you'll write the first piece of the cart. Create an empty array called $cart. Add the first product as an associative array with $cart[] using ["name" => "Pen", "price" => 25, "quantity" => 2]. Then print Cart count: 1 with echo, using count($cart) and a \n at the end of the line.

Show example solution

An empty array is created with []; a product is appended as an associative array via $cart[]. count($cart) returns the number of elements.
Example solution:
<?php
// Initialize the cart array and add the first product
$cart = [];
$cart[] = ["name" => "Pen", "price" => 25, "quantity" => 2];
echo "Cart count: " . count($cart) . "\n";

Test yourself

Why does a cart use an array?
- Because an array stores a single value
- Because it holds many products in one variable
- Because an array stores only numbers
- Because an array replaces a database
Show answer

Because it holds many products in one variable — Correct. An array holds many values in a single variable, which suits a cart.
Define an empty array
```
$cart ____;
```
Show answer
```
$cart = [];
```
Match the array concepts

Empty array

$cart = []
Append element

$cart[] = ...
Associative array

name => value
Array length

count($cart)

Project: Shopping cart