字段从未分配给它，并且将始终具有其默认值null

Question

When my program first starts, in the main method I create a new Menu which then goes to the menu class.

    private static Shop shop;
    private static Player player;

    public static void Main(string[] args)
    {
        Menu menu = new Menu();

        menu.start(menu, shop, player);
    }

In my menu class, I have a method called start(). Which prints out the options for the user.

    private Menu menu;
    private Shop shop;
    private Player player;

    public void start(Menu menu, Shop shop, Player player)
    {

        this.menu = menu;
        this.shop = shop;

Then when I compile my program, I choose to go to the shop and I get an error of 'Object reference not set to an instance of an object.'. I think I know what I have to do, but I'm not quite sure on how you do it in the main class.

I think I have to add

Shop shop

as a parameter in the Main method. Then declare

this.shop = shop;

inside the method as I have in my other classes.

I have tried doing that, but it always comes up with an error. Since it's the main method, would I have to do a different approach?

Answer 1

You have not actually allocated those static references:

private static Shop shop = new Shop();
private static Player player = new Player();