#include "stackP.h"
#include <iostream>


StackT::StackT(){
    top = nullptr;
    size = 0;
    return;
}

void StackT::Copy(const StackT & other) {
   NodeT * i,*j;

   size = other.size;
   top = nullptr;

   if (other.top != nullptr) {
       // build the first node
       top = new NodeT;
       top->data = other.top->data;
       top->next = nullptr;

       // build all other nodes
       i = top;
       j = other.top;

       while(j->next != nullptr) {
          j = j->next;
          i->next = new NodeT;
	  i = i->next;
	  i->next = nullptr;
	  i->data  = j->data;
       }

   }
   return;
}

StackT::StackT(const StackT & other) {

   Copy(other);

   return;
}

void StackT::Delete(){
   NodeT * i,*j;
   i = top;

   top = nullptr;

   while (i != nullptr) {
      j = i;
      i=i->next;
      delete j;
   }

   return;
}

StackT::~StackT(void) {
   Delete();
   return;
}

StackT & StackT::operator = (const StackT & other) {
   if (this != &other) {
       Delete();
       Copy(other);
   }

   return *this;
}

// missing routines.

void StackT::Push(ItemT i) {
     NodeT * tmp;

     size++;
     tmp = new NodeT;
     tmp->data = i;
     tmp->next = top;
     top = tmp;

     return;
}

ItemT StackT::Pop(void){
   ItemT rv;
   NodeT * tmp;

   if (top != nullptr) {
       rv = top->data;
       tmp = top;
       top = top->next;
       delete tmp;
       size--;
   }
   return rv;
}

ItemT StackT::Top(void) const{
   ItemT rv;
   if (top != nullptr) {
       rv =  top->data;
   }
   return rv;
}

int StackT::Size(void) const{
    return size;
}

bool StackT::IsEmpty(void) const{
    return top==nullptr;
}