List

#include <iostream>

struct Node {
  int Data;
  Node* Next;
  Node* Prev;

  Node(int value) : Data(value), Next(nullptr), Prev(nullptr) {}
};

int main() {
  Node* head = nullptr;
  int n = 0;
  std::cin >> n;
  for (int i = 0; i < n; ++i) {
    int value = 0;
    std::cin >> value;
    if (head == nullptr) {  // Пишут if (!head)
      head = new Node(value);
    } else {
      Node* new_node = new Node(value);
      new_node->Next = head;
      head->Prev = new_node;
      head = new_node;
    }
  }

  for (Node* c = head; c != nullptr; c = c->Next) {
    std::cout << c->Data << " ";
  }

  for (Node* c = head; c != nullptr;) {
    Node* next_after_c = c->Next;
    delete c;
    c = next_after_c;
  }

  return 0;
}