switch Statement that Practice of 3

        static void Main(string[] args) {
            const int price1 = 199, price2 = 399, price3 = 499;
            double priceTotal,selectedPrice = 0;
            Console.WriteLine("[{0}] {1,-14} {2} B.", 1, "Regular Buffet", price1);
            Console.WriteLine("[{0}] {1,-14} {2} B.", 2, "Premium Buffet", price2);
            Console.WriteLine("[{0}] {1,-14} {2} B.", 3, "Super Premium", price3);
            Console.Write("Which Buffet do you want? :");
            string choice = Console.ReadLine();
            Console.WriteLine();
            switch (choice) {
                case "1":
                    selectedPrice = price1;
                    break;
                case "2":
                    selectedPrice = price2;
                    break;
                case "3":
                    selectedPrice = price3;
                    break;
                default:
                    Console.WriteLine("Invalid Choice");
                    Environment.Exit(0);
                    break;
            }
            priceTotal = selectedPrice * readInputNumber("Number of customer");
            if(readInputYesNo("Are you member?")) {
                priceTotal -= priceTotal * 0.1;
            } else {
                priceTotal -= priceTotal * 0.05;
            }
            Console.WriteLine();
            Console.WriteLine("Your total price = {0:n} Baht.",priceTotal);

            Console.ReadKey();
        }
        static int readInputNumber(string name) {
            Console.Write("Input {0,-15} : ", name);
            return int.Parse(Console.ReadLine());
        }

        static bool readInputYesNo(string name) {
            string input;
            while (true) {
                Console.Write("{0,-21} : ", name);
                input = (Console.ReadLine()).ToLower();
                if (input == "y") {
                    return true;
                } else if (input == "n") {
                    return false;
                } else {
                    Console.WriteLine("Invalid Input!!!");
                }
            }
        }