1. internal class Program
2. {
3.     private static void Main(string[] args)
4.     {
5.         var student = new Student(22, "Jan Kowalski", new() { 4, 4, 5 });
6.         student.Hello();
7.         var elementaryStudent = new ElementaryStudent(14, "Anna Nowak", new() { 5, 5, 5 }, 32);
8.         elementaryStudent.Hello(); // Elementary Student nie implementuje swoje Hello, więc wywoła się metoda z klasy bazowej
9.         var universityStudent = new UniversityStudent(23, "John Doe", new() { 3, 3, 3 }, "C# jest super");
10.         universityStudent.Hello(); // ta klasa robi override metody virtualnej, więc wywoła się implementacja z klasy pochodnej
11.     }
12. }
13. public class Student
14. {
15.     public int Age { get; set; }
16.     public string Name { get; set; }
17.     public List<int> Grades { get; set; }
18.     public Student(int age, string name, List<int> grades)
19.     {
20.         Age = age; Name = name; Grades = grades;
21.     }
22.     public virtual void Hello()
23.     {
24.         Console.WriteLine($"My name is {Name}. My age is {Age}. My best grade is {Grades.Max()}");
25.     }
26. }
27.  
28. public class ElementaryStudent : Student
29. {
30.     public int UniformSize { get; set; }
31.     public ElementaryStudent(int age, string name, List<int> grades, int uniformSize)
32.         :base(age, name, grades)
33.     {
34.         UniformSize = uniformSize;
35.     }
36. }
37.  
38. public class UniversityStudent : Student
39. {
40.     public string ThesisTitle { get; set; }
41.     public UniversityStudent(int age, string name, List<int> grades, string thesisTitle):
42.         base(age, name, grades)
43.     {
44.         ThesisTitle = thesisTitle;
45.     }
46.  
47.     public override void Hello()
48.     {
49.         Console.WriteLine($"I'm from university. My thesis title is {ThesisTitle}");
50.     }
51. }