//Write code that prompts the user to make a choice for a pizza size - S, M, L, or X - and then displays the price as 
            //$6.99, $8.99, $12.50, or $15.00, accordingly.
            //Display an error message if the user enters an invalid pizza size. 
            //(Note: to read a char from the user use the following: ReadKey().KeyChar from the Console class).

            char[] sizes = { 'S', 'M', 'L', 'X' };
            double[] prices = { 6.99, 8.99, 12.50, 15, 00 };

            Console.Write("Enter the size of the pizza: ");
            char size = Console.ReadKey().KeyChar;
            bool valid = false; 

            for(int i = 0; i < sizes.Length; i++)
            {
                if (sizes[i] == size)
                {
                    Console.WriteLine($"\nThe price is: {prices[i]}");
                    valid = true; 
                }    
            }

            if (!valid)
            {
                Console.WriteLine("\nInvalid pizza size!!");
            }