#include <stdexcept>

#include "stack_solution.h"

Stack::Stack() : first(nullptr) {}
Stack::~Stack() { delete first; }

bool Stack::empty() const { return first == nullptr; }

void Stack::push(Stack_Data const& i)
{
  first = new Element(i, first);
}

Stack_Data Stack::pop()
{
  if ( empty() )
  {
    // std::cerr << "empty stack" << std::endl;
    throw std::logic_error("empty stack");
  }
  else
  {
    Element* victim{ first };
    Stack_Data data = victim->data;
    first = victim->next;
    victim->next = nullptr;
    delete victim;
    return data;
  }
}