Unity C# const与static readonly的区别与联系

using System;

namespace Test
{
    class MainClass
    {
        //懒人写法的单例
        class Weapon
        {
            public static readonly Weapon Instance;
            static Weapon()
            {
                Instance=new Weapon();
            }
        }
        class MyWeapon
        {
            //static readonly和const的区别
            public const int Speed=50;//const必须赋值，且只能用这种方法赋值
            //static readonly 可以赋值也可以不赋值，也可以在用static修饰的构造方法中赋值
            public static readonly int Speed_1;   
            public static readonly int Speed_2=50;
            public static readonly int Speed_3;
            static MyWeapon()
            {
                Speed_3=50;
            }
        }

        public static void Main (string[] args)
        {
            //static readonly和const的联系，
            //在外边只能通过类名.访问，且在外部不能赋值（二者都是只读的）
            Console.WriteLine (MyWeapon.Speed_3);//50
        }
    }
}