simple Func

using System;

// Func 和 Action 的唯一区别在于一个有返回值， 一个没有返回值

namespace test
{
    class Program
    {
        static void Main(string[] args)
        {
            //new ShoppingCart().Process(new Func<bool, int>(Calculator.Calculate));

            // can also be
            new ShoppingCart().Process(Calculator.Calculate);
        }
    }

    class Calculator
    {
        public static int Calculate(bool special)
        {
            int discount = 0;
            if ( special )
            {
                discount = 20;
            }
            else if (DateTime.Now.Hour < 12)
            {
                discount = 5;
            }
            else if (DateTime.Now.Hour < 20)
            {
                discount = 10;
            }
            else
            {
                discount = 15;
            }
            return discount;
        }
    }

    class ShoppingCart
    {
        public void Process(Func<bool, int> discount)
        {
            int magicDiscount = discount(false);
            int magicDiscount2 = discount(true);
            Console.WriteLine(magicDiscount);
            Console.WriteLine(magicDiscount2);
            Console.ReadLine();
        }
    }
}