static void Main(string[] args) { List <int> numbers = new List <int> { 1, 4 }; System.Console.WriteLine("Size = " + numbers.Count); System.Console.WriteLine("numbers = " + numbers[1]); Book b = new Book(); if (args.Length > 0) { Console.WriteLine($"Hello {args[0]}"); } else { Console.WriteLine("Nothing!"); } Book book1 = new Book(); book1.AddGrade(5.8); book1.AddGrade(8.5); book1.AddGrade(4.2); System.Console.WriteLine("Average = " + book1.Average()); System.Console.WriteLine("MaxGrade = " + book1.MaxGrade()); System.Console.WriteLine("MinGrade = " + book1.MinGrade()); System.Console.WriteLine("Book1 = " + book1.ToString()); }