Basic list implementation on classes in cpp

lists.cpp

#include <cstddef>
#include <iostream>

class Wezel {
public:

  Wezel(int data, Wezel* prev, Wezel* next) {
    this->data = data;
    this->prev = prev;
    this->next = next;
  }

  static Wezel* first;
  static Wezel* last;
  static int size;

  int data;
  Wezel* prev;
  Wezel* next;
};

Wezel* Wezel::first = NULL;
Wezel* Wezel::last = NULL;
int Wezel::size = 0;


void add_node(int data) {
  Wezel* nowy;
  if (Wezel::size == 0) {
    nowy = new Wezel(data, NULL, NULL);
    Wezel::first = nowy;
    Wezel::last = nowy;
  } else {
    nowy = new Wezel(data, Wezel::last, NULL);
    Wezel::last->next = nowy;
    Wezel::last = nowy;
  }
  Wezel::size++;
}


void print_nodes() {
  Wezel* current = Wezel::first;

  std::cout << "[ ";
  while (current->next != NULL) {
    std::cout << current->data << ", ";
    current = current->next;
  }
  if (current != NULL) {
    std::cout << current->data;
  }
  std::cout << " ]" << std::endl;
}

int main(int argc, char const *argv[])
{
  add_node(0);
  add_node(7);
  add_node(3);
  add_node(4756754);
  add_node(88);
  add_node(1);
  add_node(9);
  add_node(2);

  print_nodes();


  return 0;
}