private static void WriteResults(IGradeTracker book) { GradeStatistics stats = book.ComputerStatistics(); foreach (float grade in book) { Console.WriteLine(grade); } WriteResult("Average", stats.AverageGrade); WriteResult("Highest", stats.HighestGrade); WriteResult("Lowest", stats.LowestGrade); WriteResult(stats.Description, stats.LetterGrade); }