Update Stock

Part of the Logic & Flow section of Coddy's GDScript journey. Lesson 73 of 78.

Challenge

Easy

Add the command update. Keep everything you wrote in the previous steps.

A line like update Apple -20 adds -20 to the stock of Apple: a positive quantity is a delivery, a negative one takes items out.

Write the function update_stock(inventory, item, quantity) above _ready():

If the item is not in inventory, print Error: Item 'Orange' not found. (with the item name)
If the new stock would be negative, print Error: Insufficient stock for 'Apple'. and keep the old stock
Otherwise, store the new stock and print Stock for 'Apple' updated successfully.

In the loop, add an elif branch for update:

If the line does not have exactly 3 parts, print Error: Use update ITEM QUANTITY
If the quantity is not a whole number, print Error: Quantity must be an integer.
Otherwise, call update_stock()

For the commands add Apple 0.5 100, add Banana 0.2 50, add Apple 0.6 30, update Apple -20, update Banana 30, update Orange 10, update Apple -90, show and exit, the output is:

Inventory Management System
Item 'Apple' added successfully.
Item 'Banana' added successfully.
Error: Item 'Apple' already exists.
Stock for 'Apple' updated successfully.
Stock for 'Banana' updated successfully.
Error: Item 'Orange' not found.
Error: Insufficient stock for 'Apple'.
{ "Apple": { "price": 0.5, "stock": 80 }, "Banana": { "price": 0.2, "stock": 80 } }
Goodbye!

Try it yourself

extends Node

func add_item(inventory: Dictionary, item: String, price: float, stock: int) -> void:
	if inventory.has(item):
		print("Error: Item '%s' already exists." % item)
		return
	inventory[item] = {"price": price, "stock": stock}
	print("Item '%s' added successfully." % item)

func _ready():
	# The inventory: item name -> {"price": float, "stock": int}
	var inventory := {}
	print("Inventory Management System")

	while true:
		var line := OS.read_string_from_stdin()
		var parts := line.split(" ")
		var command := parts[0]

		if command == "exit":
			print("Goodbye!")
			break
		elif command == "show":
			print(inventory)
		elif command == "add":
			if parts.size() != 4:
				print("Error: Use add ITEM PRICE STOCK")
			elif not parts[2].is_valid_float() or not parts[3].is_valid_int():
				print("Error: Price and stock must be numeric.")
			else:
				add_item(inventory, parts[1], float(parts[2]), int(parts[3]))
		else:
			print("Unknown command")