using System;

using System.Collections.Generic;

public class Item

{

    public Item(string newID)

    {

        ID = newID;

    }

    public override string ToString()

    {

        return base.ToString() + " " + "ID: " + ID;

    }

    public string ID {get; set;}

}

​

public class Pet : Item

{

    public Pet(string newID): base(newID) { }

    public override string ToString()

    {

        return base.ToString() + ", " + "Category : Pet";

    }

}

​

public class Supply : Item

{

    public Supply(string newID):base(newID) { }

    public override string ToString()

    {

        return base.ToString() + ", "  + "Category : Supply";

    }

}

​

public class Program

{

    public static void Main()

    {

        /*

        Item PetFood = new Supply("0001");

        Item Dog = new Pet("0010");

        Console.WriteLine(PetFood.ToString());

        Console.WriteLine(Dog.ToString());

        */

        List<Item> Inventory = new List<Item>();

        Inventory.Add(new Pet("0001"));

        Inventory.Add(new Supply("0010"));

        Inventory.Add(new Supply("0011"));

        foreach(Item i in Inventory)

        {

            Console.WriteLine(i.ToString());    

        }

    }

}