using System;

​

public class Item

{

    private bool rare;

    private static Random r = new Random();

    private static int rareitem = 0, commonitem = 0;

    private Item(bool rare)

    {

        this.rare = rare;

        if (rare == true)

            rareitem++;

        else

            commonitem++;

    }

​

    public static Item CreateItem()

    {

        if ((r.Next(1, 11)) > 8)

            return new Item(true);

        else

            return new Item(false);

    }

​

    public static void PrintItemStats()

    {

        Console.WriteLine("rareitem:" + rareitem);

        Console.WriteLine("commonitem:" + commonitem);

    }

}

​

public class Program

{

    public static void Main()

    {

        for (int i = 0; i < 100; i++)

        {

            Item item = Item.CreateItem();

        }

​

        Item.PrintItemStats();

    }

}