// stack.h begin here
#ifndef _STACK_H_
#define _STACK_H_

typedef int Data;

class Stack
{
public:
  Stack() : mTop(0) {}
  ~Stack() { delete mTop; }

  // look at top element
  const Data& top() const;

  // look at and remove top element
  Data pop();

  // put element on top
  void push(Data&);

  // number of stored elements
  unsigned size() const;

  Stack& operator=(Stack const&);
  Stack(Stack const&);
  
private:
  class Elem
  {
  public:
    Elem(Data const& d, Elem* n = 0) : value(d), next(n) {}
    ~Elem() { delete next; }
    Elem* clone() const;
    Data value;
    Elem* next;
  };
  Elem* mTop;
};

#endif


// stack.cc begin here
#include <stdexcept>

Stack::Elem* Stack::Elem::clone() const
{
  if ( this != 0)
    return new Elem(value, next->clone());
  else
    return 0;
}

Stack& Stack::operator=(Stack const& rhs)
{
  if (this != &rhs)
  {
    Stack copy(rhs);
    Elem* save = mTop;
    mTop = copy.mTop;
    copy.mTop = save;
  }
  return *this;
}

Stack::Stack(Stack const& rhs)
{
  mTop = rhs.mTop->clone();
}

const Data& Stack::top() const
{
  if (mTop == 0)
    throw std::out_of_range("FEL: Tom stack");
  return mTop->value;
}

Data Stack::pop()
{
  Data save = top();
  Elem* victim = mTop;
  mTop = mTop->next;
  victim->next = 0; // stoppa rekursiv delete!
  delete victim;
  return save;
}

void Stack::push(Data& d)
{
  mTop = new Elem(d, mTop);
}

unsigned Stack::size() const
{
  unsigned sum = 0;
  for (Elem* c = mTop; c != 0; c = c->next)
    ++sum;
  return sum;
}

// main.cc begin here
#include <iostream>

using namespace std;

int main()
{
  Stack s;

  cout << "Mata in 10 heltal: ";
  
  // insert things in stack to test it
  for (int i = 0; i < 10; ++i)
  {
    int n;
    cin >> n;
    s.push(n);
  }

  Stack copy(s);
  
  cout << "Talen i omvänd ordning: ";
  // if they come out reverse the stack works
  for (int i = 0; i < 10; ++i)
  {
    cout << s.pop() << " ";
  }
  cout << endl;
  
  cout << "Talen i omvänd ordning: ";
  for (int i = 0; i < 10; ++i)
  {
    cout << copy.pop() << " ";
  }
  cout << endl;
  
  return 0;
}