Use of unresolved identifier 'FoodVendingMachine'

import UIKit

fileprivate let reuseIdentifier = "vendingItem"
fileprivate let screenWidth = UIScreen.main.bounds.width

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {

    @IBOutlet weak var collectionView: UICollectionView!
    @IBOutlet weak var totalLabel: UILabel!
    @IBOutlet weak var balanceLabel: UILabel!
    @IBOutlet weak var quantityLabel: UILabel!
    @IBOutlet weak var priceLabel: UILabel!

    let vendingMachine: VendingMachine

    required init?(coder aDecoder: NSCoder) {
        do {
            let dictionary = try PlistConverter.dictionary(fromFile: "VendingInventory", ofType: "plist")
            let inventory = try InventoryUnarchiver.vendingInventory(fromDictionary: dictionary)
//ERROR APPEARS BELOW
            self.vendingMachine = FoodVendingMachine(inventory: inventory)
        } catch let error {
            fatalError("\(error)")
    }
        super.init(coder: aDecoder)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        setupCollectionViewCells()
        print(vendingMachine.inventory)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Setup

    func setupCollectionViewCells() {
        let layout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 20, right: 0)

        let padding: CGFloat = 10
        let itemWidth = screenWidth/3 - padding
        let itemHeight = screenWidth/3 - padding

        layout.itemSize = CGSize(width: itemWidth, height: itemHeight)
        layout.minimumLineSpacing = 10
        layout.minimumInteritemSpacing = 10

        collectionView.collectionViewLayout = layout
    }

    // MARK: UICollectionViewDataSource

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return vendingMachine.selection.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as? VendingItemCell else { fatalError() }

        return cell
    }

    // MARK: - UICollectionViewDelegate

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        updateCell(having: indexPath, selected: true)
    }

    func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
        updateCell(having: indexPath, selected: false)
    }

    func collectionView(_ collectionView: UICollectionView, didHighlightItemAt indexPath: IndexPath) {
        updateCell(having: indexPath, selected: true)
    }

    func collectionView(_ collectionView: UICollectionView, didUnhighlightItemAt indexPath: IndexPath) {
        updateCell(having: indexPath, selected: false)
    }

    func updateCell(having indexPath: IndexPath, selected: Bool) {

        let selectedBackgroundColor = UIColor(red: 41/255.0, green: 211/255.0, blue: 241/255.0, alpha: 1.0)
        let defaultBackgroundColor = UIColor(red: 27/255.0, green: 32/255.0, blue: 36/255.0, alpha: 1.0)

        if let cell = collectionView.cellForItem(at: indexPath) {
            cell.contentView.backgroundColor = selected ? selectedBackgroundColor : defaultBackgroundColor
        }
    }


}

import Foundation

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
}

protocol VendingItem {
    var price: Double { get }
    var quantity: Int { get set }
}

protocol VendingMachine {
    var selection: [VendingSelection] { get }
    var inventory: [VendingSelection: VendingItem] { get set }
    var amountDeposited: Double { get set }
    init(inventory: [VendingSelection: VendingItem])
    func vend(_ quantity: Int, _ selection: VendingSelection) throws
    func deposit(_ amount: Double)
}

struct  Item: VendingItem {
    let price: Double
    var quantity: Int
}

//Value types: enums and structs are things
//reference types: classes do things

//below, FoodVendingMachine works better as a class
//classes are good at modeling state, that is, the particular values in our data model in a point in time
enum InventoryError: Error {
    case invalidResource
    case conversionFailure
    case invalidSelection
}

class PlistConverter {
    static func dictionary(fromFile name:String, ofType type:String) throws -> [String: AnyObject] {
        guard let path = Bundle.main.path(forResource: name, ofType: type) else {
            throw InventoryError.invalidResource        }
        guard let dictionary = NSDictionary(contentsOfFile: path) as? [String: AnyObject] else {
            throw InventoryError.conversionFailure
        }
        return dictionary
    }
}

class InventoryUnarchiver {
    static func vendingInventory(fromDictionary dictionary: [String: AnyObject]) throws -> [VendingSelection : VendingItem] {

        var inventory: [VendingSelection : VendingItem] = [:]

        for (key, value) in dictionary {
            if let itemDictionary = value as? [String: Any], let price = itemDictionary["price"] as? Double,
                let quanitity = itemDictionary["quantity"] as? Int {
                let item = Item(price: price, quantity: quanitity)

                guard let selection = VendingSelection(rawValue: key) else {
                    throw InventoryError.invalidSelection
                }
            inventory.updateValue(item, forKey: selection)
            }
        }
        return inventory
    }

}

class FoodVendingMachine: VendingMachine {
    let selection: [VendingSelection] = [.soda, .dietSoda, .chips, .cookie, .wrap, .candyBar, .sandwich, .popTart, . fruitJuice, .gum, .sportsDrink ]
    var inventory: [VendingSelection : VendingItem]
    var amountDeposited: Double = 10
    required init(inventory: [VendingSelection : VendingItem]) {
        self.inventory = inventory
    }
    func vend(_ quantity: Int, _ selection: VendingSelection) throws {

}
    func deposit(_ amount: Double) {

    }

}