using System;

​

public class Taiwan

{

    public static int Price = 0;

}

​

public class Test

{

    public void Main()

    {//↓↓↓↓↓↓整個程式碼希望變動的只有這裡↓↓↓↓↓↓

        SetPrice(new Toyota());

    }//↑↑↑↑↑↑整個程式碼希望變動的只有這裡↑↑↑↑↑

    void SetPrice(Toyota Maker)//希望本方法內的所有內容不變

    {

        Maker.Car();

        Console.WriteLine(Taiwan.Price);

    }

}

​

public class Toyota

{

    public void Car()

    {

        Taiwan.Price = 10;

    }

}

​

public class Mazda

{

    public void Car()

    {

        Taiwan.Price = 20;

    }

}

​

public class Ford

{

    public void Car()

    {

        Taiwan.Price = 30;

    }

}