#include <iostream>
#include "mySTACKS.h"
using namespace mySTACKS;

// ListStack

ListStack::Node::Node(int data, Node* next)
    : data(data), next(next)
{ }

ListStack::ListStack() {
    head = NULL;
    std::cerr << "Creating ListStack" << std::endl;
}

int ListStack::pop() {
    int   data = head->data;
    Node* temp = head->next;
    delete head;
    head = temp;
    return data;
}

void ListStack::push(int data) {
    head = new Node(data, head);
}

bool ListStack::empty() {
    return head == NULL;
}

ListStack::~ListStack() {
    std::cerr << "Deleting ListStack" << std::endl;
    while (head) {
        Node* node = head;
        head = head->next;
        std::cerr << " node " << node->data << std::endl;
        delete node;
    }
}

// ArrayStack

ArrayStack::ArrayStack() {
    top = 0;
    arr = new int[100];
    std::cerr << "Creating ArrayStack" << std::endl;
}

void ArrayStack::push(int data) {
    arr[top++] = data;
}

int ArrayStack::pop() {
    return arr[--top];
}

bool ArrayStack::empty() {
    return top == 0;
}

ArrayStack::~ArrayStack() {
    std::cerr << "Deleting ArrayStack with " << top
              << " elements remaining" << std::endl;
    delete [] arr;
}

// STACK

STACK* STACK::getInstance(int size) {
    if (size > 100)
        return new ListStack();
    else
        return new ArrayStack();
}