using System;

using ItemNamespace;                    

public class CashierApplication

{

    public static void Main()

    {

        Console.WriteLine("You are at the cashier.");

        bool run = true;

        while (run){

            Console.WriteLine("----------------");

            Console.Write("Name of item: ");

            string n = Console.ReadLine();

            Console.Write("Price: ");

            double p = double.Parse(Console.ReadLine());

            Console.Write("Quantity: ");

            int q = int.Parse(Console.ReadLine());

            Console.Write("Discount (set to 0 if none): ");

            double d = double.Parse(Console.ReadLine());

​

            DiscountItem di = new DiscountItem(n,p,q,d);

            Console.Write("Total: "+di.getTotalPrice());

            Console.Write("\nPayment: ");

            double pay = double.Parse(Console.ReadLine());

            di.setPayment(pay);

            Console.Write("Change: "+di.getChange());

            Console.WriteLine("\n----------------");

            Console.Write("\nWill you make another transaction? (yes/no): ");

            string ans = Console.ReadLine();

            if (ans == "yes"){

                run=true;

            }

            else if (ans=="no"){

                run = false;

                Console.WriteLine("Exiting program...");

            }

        }

    }

}

namespace ItemNamespace{

    public abstract class Item{

        protected string item_name;

        protected double item_price;

        protected int item_quantity;

        private double total_price;

        public Item(string name, double price, int quantity){

            this.item_name=name;

            this.item_price=price;

            this.item_quantity=quantity;

        }

        public abstract double getTotalPrice();

        public abstract void setPayment(double amount);

    }

    public class DiscountItem:Item{

        private double item_discount;

        private double discounted_price;

        private double payment_amount;

        private double change;

        public DiscountItem(string name, double price, int quantity,  double discount): base(name,price,quantity){

            this.item_discount=discount;

        }

        public override double getTotalPrice(){

            this.discounted_price = (item_price-((item_discount/100)*item_price))*item_quantity;

            return discounted_price;

        }

        public override void setPayment(double amount){

            this.payment_amount=amount;

        }

        public double getChange(){

            return payment_amount - discounted_price;

        }

    }

}

​