private static void StudentAgeOperation() { var maleBirthDate = "17.03.1992"; var femaleBirthDate = "03.11.1993"; Student maleStudent = new Student("Peter", "Ivanov"); maleStudent.AddBirthdayDate(maleBirthDate); Student femaleStudent = new Student("Stella", "Markova"); femaleStudent.AddBirthdayDate(femaleBirthDate); var olderStudent = StudentOperations.GetOlderStudent(maleStudent, femaleStudent); ConsoleWriter.Write($"The older from {maleStudent.FirstName} and {femaleStudent.FirstName} is {olderStudent.FirstName}"); }