public class Address
{
        .
        .
        .
        protected string street;
        public void setStreet(string street)
        {
            this.street = street;
        }
        .
        .
        .
}
public class Employee
{
        .
        .
        .
        protected Address address = new Address();
        public Address getAddress()
        {
            return address;
        }
        .
        .
        .
}
public class Test
{
        .
        .
        .
        public static void Main(string[] args)
        {
            Employee emp = new Employee();
            emp.getAddress().setStreet("ILLUMINATI");  <<<--------------ไม่เข้าใจบรรทัดนี้ครับ
        }
        .
        .
        .
}