private static void EnterGrades(IBook book) { while (true) { Console.WriteLine("Введите оценку или 'q' для отмены"); var input = Console.ReadLine(); if (input == "q") { break; } try { book.AddObjectGrade(input); } catch (ArgumentException ex) { Console.WriteLine(ex.Message); } catch (FormatException ex) { Console.WriteLine(ex.Message); } finally { Console.WriteLine("**"); } } }