//C#

public class Person {
 public string Name {get; set;}
 public string SurName {get; set;}
}

public class Programmer:Person {
    public String KnownLanguage {get; set;}
}

public void WriteFullName(Person p) {
 Console.WriteLine(p.Name + " " + p.SurName);   
}

var a = new Person();
a.Name = "Jan";
a.SurName = "Kowalski";

var b = new Programmer();
b.Name = "Mario";
b.SurName = "Rossi";
b.KnownLanguage = "C#";

WriteFullName(a);	// wynik: Jan Kowalski
WriteFullName(b);	// wynik: Mario Rossi