[Project] Build a small inventory system

In this lesson you combine the case classes, lists, pattern matching, and higher-order functions covered so far into a simple inventory system. It is the capstone of this Scala introduction.

Real business systems use this combination constantly: represent something like a product with a case class, manage many of them in a List, and branch on state with a match expression.

The sample code represents a product (name and quantity) with case class Item, manages the product listing in a List, and prints a per-state message with a match expression.

Immutability, pattern matching, and higher-order functions — everything covered in these lessons — are the foundations you will design around in real systems and data processing. Getting into the habit of writing small programs in a functional style is the shortest path to using Scala professionally.

📖 Reference code

case class Item(name: String, quantity: Int)

def statusOf(item: Item): String = item.quantity match {
  case 0 => "Out of stock"
  case q if q < 5 => "Low stock"
  case _ => "In stock"
}

object Main extends App {
  val items = List(
    Item("Notebook", 12),
    Item("Eraser", 3),
    Item("Ruler", 0)
  )
  for (item <- items) {
    println(s"${item.name}: ${item.quantity} (${statusOf(item)})")
  }
}

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run Scala directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).