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iOS Build a Vending Machine App in Swift 2.0 Displaying Additional Views Controlling Custom Views

Build Fail: Type 'VendingMachine' does not conform to protocol 'VendingMachineType'

I've finished the app and I have one error. The error occurs on the class VendingMachine: VendingMachineType

I have downloaded Pasan's code and I can't seem to find the discrepancy that is causing the problem. Did I miss something or am I looking in the wrong area?

Full code:

// // VendingMachine.swift // VendingMachine // // Created by Charles Di Renzo on 8/17/16. // Copyright © 2016 Treehouse. All rights reserved. //

import Foundation import UIKit


protocol VendingMachineType { var selection: [VendingSelection] { get } var inventory: [VendingSelection: ItemType] { get set } var amountDeposited: Double { get set }

init(inventory: [VendingSelection: ItemType])
func vend(selection: VendingSelection, quantity: Double) throws
func deposit(amount: Double)
func itemForCurrentSelection(selection: VendingSelection) -> ItemType?


protocol ItemType { var price: Double { get } var quantity: Double { get set } }

//Error Types

enum InventoryError: ErrorType { case InvalidResource case ConversionError case InvalidKey }

enum VendingMachineError: ErrorType { case InvalidSelection case OutOfStock case InsufficientFunds(required: Double) //this associate value will tell the user how much they have }

//Helper Classes

//this is a type method class PlistConverter { class func dictionaryFromFile(resource: String, ofType type: String) throws -> [String : AnyObject] {

    guard let path = NSBundle.mainBundle().pathForResource(resource, ofType: type) else {
            throw InventoryError.InvalidResource

    guard let dictionary = NSDictionary(contentsOfFile: path), let castDictionary = dictionary as? [String: AnyObject] else {
            throw InventoryError.ConversionError
    return castDictionary


class InventoryUnarchiver { class func vendingInventoryFromDictionary(dictionary: [String: AnyObject]) throws -> [VendingSelection : ItemType] {

    var inventory: [VendingSelection : ItemType] = [:]

    for(key, value) in dictionary {
        if let itemDict = value as? [String: Double], let price = itemDict["price"], let quantity = itemDict["quantity"] {

            let item = VendingItem(price: price, quantity: quantity)

            guard let key = VendingSelection(rawValue: key) else {
                throw InventoryError.InvalidKey

            inventory.updateValue(item, forKey: key)

        return inventory


//Concrete Types //look into raw values here, they become important

enum VendingSelection: String { case Soda case DietSoda case Chips case Cookie case Sandwich case Wrap case CandyBar case PopTart case Water case FruitJuice case SportsDrink case Gum

func icon() -> UIImage {
    if let image = UIImage(named: self.rawValue) {
        return image
    } else {
        return UIImage(named: "Default")!


struct VendingItem: ItemType { let price: Double var quantity: Double }

class VendingMachine: VendingMachineType {

let selection: [VendingSelection] = [.Soda, .DietSoda, .Chips, .Cookie, .Sandwich, .Wrap, .CandyBar, .PopTart, .Water, .FruitJuice, .SportsDrink, .Gum]

var inventory: [VendingSelection: ItemType]
var amountDesposited: Double = 10.0

required init(inventory: [VendingSelection : ItemType]) {
    self.inventory = inventory

func vend(selection: VendingSelection, quantity: Double) throws {
    guard var item = inventory[selection] else {
        throw VendingMachineError.InvalidSelection

    guard item.quantity > 0 else {
        throw VendingMachineError.OutOfStock
    //at this point we have an item and a quantity implement a cancel button as homework here. 

    //time to reduce quantity by amount purchased

    item.quantity -= quantity
    inventory.updateValue(item, forKey: selection)

    //here we are checking to see if we have enough money and throwing an error if they do not
    let totalPrice = item.price * quantity
    if amountDesposited >= totalPrice {
        amountDesposited -= totalPrice
    } else {
        let amountRequired = totalPrice - amountDesposited
        throw VendingMachineError.InsufficientFunds(required: amountRequired)

func itemForCurrentSelection(selection: VendingSelection) -> ItemType? {
    return inventory[selection]

func deposit(amount: Double) {
    amountDesposited += amount


2,180 Points

I've got the same problem and I fixed it in this way:

struct VendingItem: ItemType {
    let price: Double = 0.0
    var quantity: Double = 0.0
    var amountDeposited: Double = 0.0

But I still don't understand why it's working in the video and not in my compiler. Maybe the version of Swift is slightly different.