oop/event stuffs

using System;
using System.Collections.Generic;
using System.Threading;

class Program
{
    static void Main(string[] args)
    {

        var player1 = new Player("player 1");
        var player2 = new Player("player 2");

        var game = new Game1();

        var running = true;

        while (running)
        {
            game.Update();
            game.Draw();
            Thread.Sleep(100);
        }
    }
}

public class Game1
{
    public delegate void UpdateDelegate();
    public delegate void DrawDelegate();

    public static event UpdateDelegate UpdateHandler;
    public static event DrawDelegate DrawHandler;

    public void Update()
    {
        //the ? is a null check
        UpdateHandler?.Invoke();
    }

    public void Draw()
    {
        DrawHandler?.Invoke();

    }

}

public abstract class Entity
{
    // static fields
    public static List<Entity> entities = new List<Entity>();

    //static constructor, run before anything is instantiated
    static Entity()
    {
        //adding the update methods to the game events
        Game1.UpdateHandler += UpdateAll;
        Game1.DrawHandler += DrawAll;
    }

    // static methods
    public static void UpdateAll() // called from game1 event invocation
    {
        foreach (Entity entity in entities) entity.Update();
    }

    public static void DrawAll() // called from game1 event invocation
    {
        foreach (Entity entity in entities) entity.Draw();
    }



    // instance fields

    public string name;
    //public Vector3 position;
    //...

    //constructor
    public Entity()
    {

        Console.WriteLine("Entity " + name + " added to entities list");
        entities.Add(this);
    }

    //abstract intsance methods, these must be inherited
    public abstract void Update();
    public abstract void Draw();
}

public class Player : Entity
{

    public Player(string name)
    {
        //base class is also run to add it to the entities list in the base class
        Console.WriteLine("new player:" + name);
        this.name = name;
    }

    public override void Update()
    {
        Console.WriteLine("update:" + name);
        //this is called via the Entity UpdateAll() static method
    }

    public override void Draw()
    {
        Console.WriteLine("draw: " + name);
        //this is called via the Entity UpdateAll() static method
    }
}