C#關鍵字集合IDictionaryC#基礎學習

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

using System.Collections;

namespace day01
{
    class Class27
    {
        static void Main(string[] args)
        {
            Cat catDictionary = new Cat();
            catDictionary.Add("1001", new Cat("zhangsan"));
            catDictionary.Add("1002", new Cat("lisi"));
            catDictionary.Add("1003", new Cat("wangwu"));

            foreach(DictionaryEntry entry in catDictionary)
            {
                Console.WriteLine("{0} {1}", entry.Value.ToString(), ((Animal)entry.Value).Name);
            }

            Console.WriteLine(catDictionary["1003"].ToString());
            Console.WriteLine(catDictionary["1003"].Name);
            Console.ReadKey();
        }
    }
    public abstract class Animal : DictionaryBase
    {
        protected string name;
        public string Name { get; set; }
        public Animal()
        {
            Name = "default";
        }
        public Animal(string name)
        {
            Name = name;
        }
        public abstract void Run();
        public abstract void Sleep();
        public override string ToString()
        {
            return "name: " + Name;
        }
        public void Add(string newId,Animal animal)
        {
            Dictionary.Add(newId, animal);
        }
        public void Remove(string newId)
        {
            Dictionary.Remove(newId);
        }
        public Animal this[string newId]
        {
            get
            {
                return (Animal)Dictionary[newId];
            }
            set
            {
                Dictionary[newId] = value;
            }
        }
    }
    public class Cat : Animal
    {
        //這個構造器該怎么理解？
        public Cat()
        {

        }
        public Cat(string name) : base(name)
        {

        }
        public override void Run()
        {
            Console.WriteLine("animal name: {0} is running", Name);
        }

        public override void Sleep()
        {
            Console.WriteLine("animal name: {0} is sleeping", Name);
        }
    }
}