#include "Stack.h"


// Note: if you get an error about nullptr, try using -std=c++0x commandline switch
// or whatever compiler switch forces C++11 standard compiling (-std=c++0x is for g++).

// Stack class
template<class T>
Stack<T>::Stack()
{
	top = nullptr; //10
}

// Push
template<class T>
void Stack<T>::push(T newItem)
{
	StackNode<T> *newNode = new StackNode<T>(newItem, top); //17 - top is a private pointer for the class Stack class (header)
	top = newNode; //18
}

// Peek
template<class T>
T Stack<T>::peek()
{
	if (!isEmpty()) return top ->getData(); //try to avoid checking for nullptr.
}

// Pop
template<class T>
T Stack<T>::pop()
{
	T data = peek(); //local variable of type T called data
	StackNode<T> *temp = top; //if top is not empty, want to be able to remove it.
	if (!isEmpty())
	{
		top = top ->getNext(); //top becomes top's next
		delete temp;	//delete the original top data.
	}
	return data;
}

// isEmpty
template<class T>
bool Stack<T>::isEmpty()
{
	return top == nullptr; //if top is not nullptr, then returns falls. is empty? returns true.
}

// clear
template<class T>
void Stack<T>::clear()
{

	StackNode<T> *current = top; //traversal woo

	if (current == nullptr)
	{
		std::cout << "Stack is empty, nothing to clear." << std::endl;
	}
	else
	{
		while (current != nullptr)  //while current is not a null value
		{
			StackNode<T> *temp = current;
			current = current->getNext();
			delete temp;
		}
	}
}

// display stack contents
template<class T>
void Stack<T>::display()
{
	StackNode<T> *current = top;
	if (current == nullptr)
	{
		std::cout << "Stack is empty, nothing to display." << std::endl;
	}
	else
	{
		std::cout << "T: ";

		while (current != nullptr)
		{
			std::cout << "{" << current->getData() << "}";
			current = current->getNext();
		}

		std::cout << std::endl;
	}
}