using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Customer cust = new Customer();

        cust.DicountGroup = new FreqentDiscount();

        Product prod = new Product();

        prod.UnitPrice = 120;

        ProductPriceCalculatorOOP calc = new ProductPriceCalculatorOOP();

        Console.WriteLine(calc.GetMaximumDiscountPrice(cust, prod));

    }

}

​

public class Customer

{

    public string FullName

    {

        get;

        set;

    }

​

    public IDiscount DicountGroup

    {

        get;

        set;

    }

}

​

public class Product

{

    public string PoductName

    {

        get;

        set;

    }

​

    public decimal UnitPrice

    {

        get;

        set;

    }

}

​

public interface IDiscount

{

    decimal CalculateDiscount(decimal price);

}

​

public class EmployeeDiscount : IDiscount

{

    public decimal CalculateDiscount(decimal price)

    {

        decimal discount = price * (decimal).20;

        return discount;

    }

}

​

public class VIPDiscount : IDiscount

{

    public decimal CalculateDiscount(decimal price)

    {

        decimal discount = price * (decimal).10;

        return discount;

    }

}

​

public class FreqentDiscount : IDiscount

{

    public decimal CalculateDiscount(decimal price)

    {

        decimal discount = price * (decimal).05;

        return discount;

    }

}

​

​

public class ProductPriceCalculatorOOP

{

    public decimal GetMaximumDiscountPrice(Customer cust, Product product)

    {

        decimal employeeDiscount = cust.DicountGroup.CalculateDiscount(product.UnitPrice);

        decimal firstDayDiscount = 0;

        if (product.UnitPrice > 100 && DateTime.Now.Day == 1)

        {

            firstDayDiscount = 25;

        }

​

        decimal maxDiscount = employeeDiscount > firstDayDiscount ? employeeDiscount : firstDayDiscount;

        return product.UnitPrice - maxDiscount;

    }

}