// File: HStack.cpp
//
// Implementation of heterogeneous stack 
//

#include "HStack.h"

// Default constructor
//
HStack::HStack() {
   // everything done by HList constructor
}


// Copy Constructor
//
HStack::HStack(const HStack& S) : HList(S) {
   // everything done by HList copy constructor
}


// Destructor
//
HStack::~HStack() {
   // everything done by HList destructor
}


// Assignment
const HStack& HStack::operator=(const HStack& rhs) {

  HList::operator=(rhs) ;
  return *this ;
}


// Rename HList operations 
//
void HStack::push(HNode *ptr) {
   push_front(ptr) ;
}

void HStack::pop() {
   pop_front() ;
}

HNode *HStack::top() {
   return front() ;
}


ostream& operator<< (ostream& os, const HStack& S) {
   S.print(os) ; 
   return os ;
}