namespace 重寫
{
    class Parent
    {
        public void F()
        {
            Console.WriteLine("Parent.F()");
        }
        //重寫的屬性必須是virtual、abstract或override
        public virtual void G() //虛方法
        {
            Console.WriteLine("Parent.G()");
        }
    }
    class ChildOne : Parent //子類一繼承父類
    {
        new public void F() //覆寫(overwrite)父類函數
        {
            Console.WriteLine("ChildOne.F()");
        }
        public override void G() //重寫(override)父類虛函數,主要實現多態(tài)
        {
            Console.WriteLine("ChildOne.G()");
        }
    }

    class ChildTwo : Parent //子類二繼承父類
    {
        new public void F()
        {
            Console.WriteLine("ChildTwo.F()");
        }
        public override void G()
        {
            Console.WriteLine("ChildTwo.G()");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Parent childOne = new ChildOne();
            Parent childTwo = new ChildTwo();
            //調用Parent.F()
            childOne.F();
            childTwo.F();
            //實現多態(tài)
            childOne.G();
            childTwo.G();
        }
    }
}