Swift 4 - Object Oriented Programming Playground

OOP.swift

//: Playground - noun: a place where people can play

import UIKit

print("Object Oriented Programming")

// Protocal

protocol PurchaseItem {
    func cost() -> Float
    func description() -> String
}

// Product

struct Apple: PurchaseItem {
    let name: String
    let price: Float
    
    func cost() -> Float {
        return price
    }
    func description() -> String {
        return "\(name) : \(price)"
    }
}

struct Beef: PurchaseItem {
    let name: String
    let weight: Float
    let pricePerWeight: Float
    
    func cost() -> Float {
        return weight * pricePerWeight
    }
    func description() -> String {
        return "\(name) : Weight \(weight), Peice per weight \(pricePerWeight)"
    }
}

struct Fish: PurchaseItem {
    let name: String
    let price: Float
    
    func cost() -> Float {
        return price
    }
    func description() -> String {
        return "\(name) : \(price)"
    }
}

// Customer

struct Customer {
    let name: String
    let purchaseItems: [PurchaseItem]
}

// Supershop

struct SuperShop {
    func printReceipt(customer: Customer) {
        print("Print Receipt for customer \(customer.name)")
        
        print("Description : \(customer.purchaseItems.reduce("", {$0 + "\n" + $1.description()}))")
        print("Total : \(customer.purchaseItems.reduce(0, {$0 + $1.cost()}))")
        
        /* Able to remove this code by using hig order "reduce" method by removing forEach codebase
        var total: Float = 0
        customer.purchaseItems.forEach { (item) in
            
            total += item.cost()
            print(item.description())
            /* Able to remove this code by defining let purchaseItems: [PurchaseItem] from let purchaseItems: [Any]
            if let purchaseItem = item as? PurchaseItem {
                total += purchaseItem.cost()
                print(purchaseItem.description())
            }
            */
            
            /* Able to remove this code by implimentin PurchaseItem protocol and cost, description func of that protocol
            if let apple = item as? Apple {
                print("\(apple.name) : \(apple.price)")
                total += apple.price
            } else if let beef = item as? Beef {
                print("\(beef.name) : Weight\(beef.weight), Price per Weight \(beef.pricePerWeight)")
                total += beef.weight * beef.pricePerWeight
            } else if let fish = item as? Fish {
                print("\(fish.name) : \(fish.price)")
                total += fish.price
            }
            */
        }
        print("Total : \(total)")
        */
    }
}

let greenApple = Apple(name: "Green Apple", price: 50.0)
let redApple = Apple(name: "Red Apple", price: 40)

let localBeef = Beef(name: "Local Beef", weight: 2.5, pricePerWeight: 500)

let ilishFish = Fish(name: "Padma Ilish", price: 1200)

let customer = Customer(name: "Raju", purchaseItems: [greenApple, redApple, localBeef, ilishFish])

let shwapno = SuperShop()
shwapno.printReceipt(customer: customer)