#include <iostream>

using namespace std;

struct Node {
  char data;
  Node* next;
};

class Stack {
  public:
    Node* head;
    void add(char value);
    void output();
    Stack();
    ~Stack();
};

int main() {
  Stack stack1;
  stack1.add('h');
  stack1.add('e');
  stack1.add('l');
  stack1.add('l');
  stack1.add('o');
  stack1.output();

  return 0;
}

Stack::Stack()
  :head(NULL) {}

Stack::~Stack() {
  Node* cursor = head;
  while (cursor != NULL) {
    Node* next = cursor->next;
    delete cursor;
    cursor = NULL;
    cursor = next;
  }
}

void Stack::add(char value) {
  Node* node = new Node;
  node->data = value;
  node->next = head;
  head = node;
}

void Stack::output() {
  Node* cursor = head;
  if (cursor) {
    while (cursor->next) {
      cout << cursor->data << endl;
      cursor = cursor->next;
    }
    cout << cursor->data << endl;
  }
}