Задача 12

using System;
using System.Collections.Generic;

namespace С
{
    class Person
    {
        public string FullName { get; set; }
        public DateTime BirthDate { get; set; }
        public bool IsMale { get; set; }

        public virtual void ShowInfo()
        {
            Console.WriteLine($"ФИО {FullName}, Дата рождения {BirthDate}, Пол {(IsMale ? "Мужской" : "Женский")}");
        }


    }
    class Student : Person
    {
        public string Institute { get; set; }
        public string Speciality { get; set; }

        public override void ShowInfo()
        {
            base.ShowInfo();
            Console.WriteLine($"Институт {Institute}, Специальность {Speciality}");
        }

        public void NewMethod()
        {
            Console.WriteLine("NewMethod");
        }
    }

    class Employee : Person
    {
        public string CompanyName { get; set; }
        public string Post { get; set; }
        public decimal Salary { get; set; }
        public override void ShowInfo()
        {
            base.ShowInfo();
            Console.WriteLine($"Компания {CompanyName}, Должность {Post}, Зарплата {Salary}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Person[] arr= { new Person() { FullName = "Иванов И. И.", BirthDate = DateTime.Now, IsMale = true },
                new Student() {FullName = "2Иванов И. И.", BirthDate = DateTime.Now, IsMale = true, Institute = "HSE", Speciality="PI"  },
            new Employee() { FullName = "3Иванов И. И.", BirthDate = DateTime.Now, IsMale = true, CompanyName = "R", Post="1",
            Salary = 100000} };

            foreach (var item in arr)
            {
                item.ShowInfo();
                if(item is Student)
                {
                    ((Student)item).NewMethod();
                }
            }
        }
    }
}