12_5

 abstract public class Person: IComparable
    {
        abstract public void Print();
        abstract public int Age();
        public int CompareTo(object obj)
        {
            Person a = (Person) obj;
            if (this.Age() == a.Age()) return 0;
            else if (this.Age() < a.Age()) return -1;
            else return 1;
        }
    }

 class Enrollee: Person
    {
        private string name;
        private string DOB;
        private string faculty;

        public Enrollee (string _name, string _DOB, string _faculty)
        {
            name = _name;
            DOB = _DOB;
            faculty = _faculty;
        }

        public override void Print()
        {
            Console.Write("{0}, {1}, {2}, ", name, DOB, faculty);
        }

        public override int Age()
        {
            string time = DateTime.Now.ToShortDateString();
            int day1 = int.Parse(DOB.Substring(0, 2));
            int month1 = int.Parse(DOB.Substring(3, 2));
            int year1 = int.Parse(DOB.Substring(6));
            int day2 = int.Parse(time.Substring(0, 2));
            int month2 = int.Parse(time.Substring(3, 2));
            int year2 = int.Parse(time.Substring(6));
            if (month1 < month2) return year2 - year1;
            else if (month1 == month2)
            {
                if (day1 <= day2)
                    return year2 - year1;
                else return year2 - year1 - 1;
            }
            else return year2 - year1 - 1;
        }
    }

class Student: Person
    {
        private string name;
        private string DOB;
        private string faculty;
        private int course;

        public Student(string _name, string _DOB, string _faculty, int _course)
        {
            name = _name;
            DOB = _DOB;
            faculty = _faculty;
            course = _course;
        }

        public override void Print ()
        {
            Console.Write("{0}, {1}, {2}, {3}, ", name, DOB, faculty, course);
        }

        public override int Age()
        {
            string time = DateTime.Now.ToShortDateString();
            int day1 = int.Parse(DOB.Substring(0, 2));
            int month1 = int.Parse(DOB.Substring(3, 2));
            int year1 = int.Parse(DOB.Substring(6));
            int day2 = int.Parse(time.Substring(0, 2));
            int month2 = int.Parse(time.Substring(3, 2));
            int year2 = int.Parse(time.Substring(6));
            if (month1 < month2) return year2 - year1;
            else if (month1 == month2)
            {
                if (day1 <= day2)
                    return year2 - year1;
                else return year2 - year1 - 1;
            }
            else return year2 - year1 - 1;
        }
    }

 class Teacher: Person
    {
        private string name;
        private string DOB;
        private string faculty;
        private string post;
        private int experience;

        public Teacher (string _name, string _DOB, string _faculty, string _post, int _experience)
        {
            name = _name;
            DOB = _DOB;
            faculty = _faculty;
            post = _post;
            experience = _experience;
        }

        public override void Print ()
        {
            Console.Write("{0}, {1}, {2}, {3}, {4}, ",name, DOB, faculty, post, experience);
        }

        public override int Age()
        {
            string time = DateTime.Now.ToShortDateString();
            int day1 = int.Parse(DOB.Substring(0, 2));
            int month1 = int.Parse(DOB.Substring(3, 2));
            int year1 = int.Parse(DOB.Substring(6));
            int day2 = int.Parse(time.Substring(0, 2));
            int month2 = int.Parse(time.Substring(3, 2));
            int year2 = int.Parse(time.Substring(6));
            if (month1 < month2) return year2 - year1;
            else if (month1 == month2)
            {
                if (day1 <= day2)
                    return year2 - year1;
                else return year2 - year1 - 1;
            }
            else return year2 - year1 - 1;
        }
    }

 class Program
    {
        static void Print(List<Person> list)
        {
                foreach (Person item in list)
                {
                    item.Print();
                    Console.WriteLine("{0}", item.Age());
                }
        }

        static List<Person> Read()
        {
            using (StreamReader fin = new StreamReader("D:/input.txt"))
            {
                int n = int.Parse(fin.ReadLine());
                List<Person> list = new List<Person>();
                for (int i = 0; i < n; i++)
                {
                    string[] text = fin.ReadLine().Split(' ');
                    if (text.Length == 3)
                        list.Add(new Enrollee(text[0], text[1], text[2]));
                    else if (text.Length == 4)
                        list.Add(new Student(text[0], text[1], text[2], int.Parse(text[3])));
                    else if (text.Length == 5)
                        list.Add(new Teacher(text[0], text[1], text[2], text[3], int.Parse(text[4])));
                    else Console.WriteLine("В {0}-ой строчке ошибка в данных", i+1);
                }
                return list;
            }
        }

        static void Search(List<Person> list)
        {
            Console.WriteLine("Enter range og the age a: ");
            int a = int.Parse(Console.ReadLine());
            Console.WriteLine("b: ");
            int b = int.Parse(Console.ReadLine());
            foreach (Person item in list)
            {
                if ((item.Age() >= a) && (item.Age() <= b))
                {
                    item.Print();
                    Console.WriteLine(item.Age());
                }
            }
        }

        static void Main(string[] args)

       {
            List<Person> list = Read();
            Print(list);
            Search(list);
            Console.WriteLine();
            list.Sort();
            Print(list);
        }

10
Akunin 15.12.1996 Biofac 4
Fedorov 21.12.2001 Himfac
Chernov 30.04.1947 Fisfac 3
Gorina 26.01.1982 IFIG assistent 5
Kuzmina 15.03.1973 KNIIT
Leshin 01.09.1976 NLP dotzent 12
Kudrin 03.11.1994 Fisfac
Rodnin 30.11.1973 Himfac
Voevodina 01.12.1969 KNIIT prepodavatel' 23
Burkina 29.11.1996 KNIIT 1