téglalap

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

namespace ConsoleApplication1
{
  class Elso
  {
    protected int a, b;
    public void Be_a(int x)
    {
      a = x;
    }
    public void Be_b(int x)
    {
      b = x;
    }
    public void Be_ab(int x, int y)
    {
      a = x;
      b = y;
    }
    public int Ki_a()
    {
      return a;
    }
    public int Ki_b()
    {
      return b;
    }
    public int Kerulet()
    {
      return 2 * (a + b);
    }
  }
  class Masodik : Elso
  {
    public int Kerulet()
    {
      return a + b;
    }
  }
  class Program
  {
    static void Main(string[] args)
    {
      List<Masodik> teglalap = new List<Masodik>();
      int? akarmi = 3;
      for (int i = 0; i < 5; i++)
      {
        Masodik x = new Masodik();
        x.Be_ab(i + 1, i + 1);
        teglalap.Add(x);
      }
      foreach (Masodik x in teglalap)
      {
        Console.WriteLine(x.Kerulet());
      }
      Console.ReadKey();

    }
  }
}