Лекция

struct Node {
    int val;
    Node* next;

    Node(int _val) : val(_val), next(nullptr) {};
};

void printNode(Node* t){
    while(t != nullptr){
        cout << t->val << ' ';
        t = t->next;
    }
    cout << "\n";
}

Node* reverse(Node* now, Node* pr){
    if(now == nullptr)
        return pr;

    Node* tNext = now->next;
    now->next = pr;
    return reverse(tNext, now);
}

int main() {
    int n = 5;

//    cin >> n;

    Node* head = new Node(0);
    Node* pred = head;

    for(int i = 1; i<n; i++){
        Node* t = new Node(i);
        pred->next = t;
        pred = t;
    }

    printNode(head);

    head = reverse(head, nullptr);

    printNode(head);

    return 0;
}