#pragma once
#include <iostream>
#include <string>
using namespace std;

class stack
{
public:
	string * items; //the array
	int numItems; //number items in stack
	int capacity; //size of current items array

	//Default constructor
	stack()
	{
		capacity = 5;
		items = new string[5];
		numItems = 0;
	}

	//parameterized constructor
	stack(int cap)
	{
		capacity = cap;
		items = new string[cap];
		numItems = 0;
	}

	//A helper method to resize the given 
	//array to a larger given value.
	//Run time: O(n)
	void resize(int newCap)
	{
		//Step 0: For fun, announce what you are resizing too:
		cout << "Resizing array to " << newCap << endl;

		//Step 1: Make a new array of size newCap
		string* bigArray = new string[newCap];

		//Step 2: Copy items over from old array to new array
		for (int i = 0; i < capacity; i++)
		{
			bigArray[i] = items[i];
		}

		//Step 2.5:  clean up (delete) old array to prevent memory leak
		delete [] items;

		//Step 3: point items variable to the new, bigger array
		items = bigArray;

		//Step 4: Update capacity variable
		capacity = newCap;

	}


	//Add item x to top of stack
	//Run time: Depends... if it has to resize, O(n)
	//						if not, O(1)
	//
	void push(string x)
	{
		if (numItems == capacity)
		{
			//out of room!
			resize(2*capacity);
		}

		items[numItems] = x;
		numItems++;
	}

	//Remove and return top item from stack
	string pop()
	{
		numItems--;
		return items[numItems];
	}

	//Determine if stack is empty
	bool empty()
	{
		if (numItems == 0)
			return true;
		else
			return false;
	}
};