C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Inheritance_practice
{
    class Person
    {
        protected string _name;
        protected string _family;
        protected int _age;

        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }

        public string Family
        {
            get { return _family; }
            set { _family = value; }
        }

        public int Aage
        {
            get { return _age; }
            set {
                    _age = value;
                    if (value > 100)
                     {
                        throw new ArgumentException(string.Format("Error.... !"));
                      }
                }
        }

        public Person(string name, string family, int age)
        {
            this._name = name;
            this._family = family;
            this._age = age;

        }
        public Person()
        {
        }

        //public override string ToString()
        //{
        //    return string.Format("Name: {0}\nSurname: {1}\nAge: {2}",name, family, age);
        //}
        
        }

    }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Inheritance_practice
{
    class Student:Person
    {
        private string _id;
        public string Id
        {
            get { return _id; }
            set { _id = value;}
        }
        public Student(string name, string family, int age, string id)
            : base(name, family, age)
        {
            this._id = id;
        }
        public Student()
        {
        }



        public override string ToString()
        {
            return string.Format("Name: {0}\nSurname: {1}\nAge: {2}\nId: {3}", _name, _family, _age, _id);
                
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Inheritance_practice
{
    class Program
    {
        static void Main(string[] args)
        {
            Person p = new Person("Ali","Moradpour",28);
            Student s = new Student();
            s.Id = "30069802";



            Console.WriteLine(p);
            Console.WriteLine(s);
            Console.ReadKey();
        }
    }
}

class Example4
{
    public static void Test()
    {
        Base4 one = new SubClass4_1();
        Base4 two = new SubClass4_2();
        one.Go();
        two.Go();
        System.Threading.Thread.Sleep(20000); //give the threads time to do stuff before terminating
        one.Stop();
        two.Stop();
    }
}

abstract class Base4
{
    DateTime lastRun = DateTime.UtcNow;
    Timer timer = new Timer();
    public void Go()
    {
        timer.AutoReset = false; //run once (until manually enabled in Again())
        timer.Elapsed += new ElapsedEventHandler(OnElapsedTime);
        timer.Interval = GetInterval();
        timer.Enabled = true;
    }
    public void Stop()
    {
        timer.Close();
        timer.Dispose();
        //nb: code in thread runs to completion even after timer has been disposed of
    }
    private void OnElapsedTime(object source, ElapsedEventArgs e)
    {
        lastRun = DateTime.UtcNow;
        RunSubClassCode();
        Again();
    }

    private void Again()
    {
        //acount for delay caused by the app running
        int interval = GetIntervalAccountForProcessingTime();
        try //stops the "loop" when the timer is disposed of, without exception
        {
            timer.Interval = interval;
            timer.Enabled = true;//kick things off again
        }
        catch (ObjectDisposedException) { }

    }
    private int GetIntervalAccountForProcessingTime()
    {
        int interval = GetInterval();
        interval -= DateTime.UtcNow.Subtract(lastRun).Milliseconds;
        interval = Math.Max(interval, 1);                                   //if we've gone past the period, kick it off straight away
        //while (interval < GetInterval()) interval += GetInterval();       //if we want to wait for the next interval/slot, replace the above line with this code
        return interval;
    }
    protected abstract int GetInterval();
    protected abstract void RunSubClassCode();
}

class SubClass4_1 : Base4
{
    protected override void RunSubClassCode()
    {
        Console.WriteLine("1a" + DateTime.UtcNow.ToString("mm ss ffff"));//easy way to see when things are kicking off
        System.Threading.Thread.Sleep(2000);
        Console.WriteLine("1b");
    }
    protected override int GetInterval()
    {
        return 3000;
    }
}
class SubClass4_2 : Base4
{
    protected override void RunSubClassCode()
    {
        Console.WriteLine("2a" + DateTime.UtcNow.ToString("mm ss ffff"));//easy way to see when things are kicking off
        System.Threading.Thread.Sleep(2000);
        Console.WriteLine("2b");
    }
    protected override int GetInterval()
    {
        return 2000;
    }
}

[assembly: AssemblyVersion("1.2.*.*")]