#include "stack.h"
#include <stdlib.h>
#include <assert.h>

Stack::~Stack()
{
   stackPtr tmp;

   while (s != NULL)
   {
      tmp = s;
      s = s->next;
      delete tmp;
      tmp = NULL;
   }
}

Stack::Stack(const Stack& oldStack)
{
   stackPtr oldPtr = oldStack.s;
   stackPtr ptr;

   if (oldStack.s == NULL)
   {
      s = NULL;
      return;
   }
   else
   {
      s = new stackItem;
      assert (s != NULL);
      ptr = s;
      ptr->next = NULL;
      ptr->value = oldPtr->value;
      oldPtr = oldPtr->next;
   }

   while (oldPtr != NULL)
   {
      ptr->next = new stackItem;
      assert (ptr->next != NULL);
      ptr = ptr->next;
      ptr->next = NULL;
      ptr->value = oldPtr->value;
      oldPtr = oldPtr->next;
   }
}

int Stack::StackIsEmpty(void)
{
   return s == NULL;
}

void Stack::Push(int newItem, int& success)
{
   stackPtr tmp;

   tmp = new stackItem;

   if (!(success = tmp != NULL))
      return;

   tmp->value = newItem;
   tmp->next = s;
   s = tmp;
}

void Stack::Pop(int& success)
{
   stackPtr tmp;

   if (s == NULL)
      success = 0;
   else
   {
      success = 1;
      tmp = s;
      s = s->next;
      delete tmp;
   }
}

void Stack::GetStackTop(int& stackTop, int& success)
{
   if (s == NULL)
      success = 0;
   else
   {
      success = 1;
      stackTop = s->value;
   }
}