ReadList

#include <iostream>

using namespace std;

struct Node {
  int data;
  Node* next;

  Node(int x) : data(x), next(nullptr) {}
};

int main() {
  // 1 2 3 0
  Node* head = nullptr;
  int x = 0;
  Node* cur = nullptr;
  while (cin >> x, x != 0) {
    if (cur) {
      cur = cur->next = new Node(x);
    } else {
      head = cur = new Node(x);
    }
  }

  for (cur = head; cur; cur = cur->next) {
    cout << cur->data << " ";
  }
  for (cur = head; cur;) {
    Node* to_delete = cur;
    cur = cur->next;
    delete to_delete;
  }
  return 0;
}