static void Main(string[] args) { GradeAddedDelegate logger = (object sender, EventArgs eventArguments) => { Console.WriteLine($"GradeAdded: {sender.ToString()}"); }; var demo = new Book("Demo"); demo.GradeAdded += logger; demo.GradeAdded += GradesCounter; demo.AddGrade(95); demo.AddGrade(50); demo.AddGrade(90); demo.AddGrade(100); demo.AddGrade(83.3); Console.WriteLine($"Grades Added: {counter}."); Console.WriteLine(demo.ToString()); Console.WriteLine(demo.GetStatistics().ToString()); }