static constracutor in c#

By ussing static constracutor we can intialize the static variable
 *we can not use access modifier(public,private..) by declaring static constructor
 *Static constructor can not take parameter.

Sample code 1:

public partial class static_constructor : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
     {
        Doctor d1=new Doctor(50,"ramesh");
        Doctor d2=new Doctor(55,"bikash");
        Response.Write(d1.age);
        Response.Write(d1.name);
        Response.Write(d2.age);
        Response.Write(d2.name);
        Response.Write(Doctor.address);
        }
}
public class Doctor
{
    public int age;
    public string name;
    public static string address; // here all doctor address is same then we need 3 time declare hence we use static constructor
    public Doctor(int age, string name)
    {
        this.age = age;
        this.name = name;
    }
    static Doctor()  // this is called static constructor( not taken any access modifier)
    {
        address = "Bangalore";
    }
}

Sample code2 :

public partial class static_constructor2 : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        A a1 = new A(21);

        Response.Write(a1.y);

    }

}

public class A

{

    private static int x;

    static A()

    {

        x = 20;

    }

    public int y;

    public A(int y)

    {

        this.y = y;

    }

}

public class B : A

{

    public static int x1;

    public int y1;

    public B(int y1):base(y1)    // here if u supposed to not write base keyword it will not be work

    {

        this.y1 = y1;

    }

}