Adding three static fields

Question

In the below code if we use constant fields, Result will be OK! but when we use static field, the result isn't expected.

Why and How?

class Program
{
    private static int x = y + 100;
    private static int y = z - 10;
    private static int z = 300;

    public static void Main(string[] args)
    {
        System.Console.WriteLine("{0}/{1}/{2}",x,y,z); // 100/-10/300  why and how?
        Console.ReadKey();
    }
}

Answer 1

Member variables are initialized in the order they appear in the file. At the time x is initialized, y and z are both 0.