namespace WhileLoops
{
    class Program
    {
        static void Main(string[] args)
        {
            bool displayMenu = true;

            while (displayMenu)
            {
                displayMenu = MainMenu();
            }
        }
        private static bool MainMenu()
        {
            Console.WriteLine("Choose an option:  ");
            Console.WriteLine("1) Option 1 ");
            Console.WriteLine("2) Option 2 ");
            Console.WriteLine("3) Exit");
            string result = Console.ReadLine();

            if (result == "1")
            {
                Option1();
                return true;
            }
            else if (result == "2")
            {
                Option2();
                return true;
            }
            else if (result == "3")
            {
                Exit();
                return false;
            }
            else
            {
                InvalidInput();
                return true;
            }
        }
        private static void Option1()
        {
            Console.WriteLine("Option 1 sub-menu");
            Console.ReadLine();
        }
        private static void Option2()
        {
            Console.WriteLine("Option 2 sub-menu");
            Console.ReadLine();
        }
        private static void Exit()
        {

        }
        private static void InvalidInput()
        {
            Console.WriteLine("Sorry, we do not understand");
            Console.ReadLine();
        }
    }
}