#pragma once

class stack
{
private:
	//Let's declare some variables
	double* items;

	//size of current array
	int capacity;

	//number of items currently in the stack
	int numItems;

public:
	stack()
	{
		items = new double[5];
		capacity = 5;
		numItems = 0;
	}

	void resize(int newCapacity)
	{
		//Step 1: create a new (bigger) array
		double* otherArray = new double[newCapacity];

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

		//Step 3: update the capacity
		capacity = newCapacity;

		//Step 3.5: free the old array memory
		delete[] items;

		//Step 4: Set array variable to point at the new (bigger) array
		items = otherArray;
	}

	void push(double x)
	{
		//First check if we are out of room
		if (numItems == capacity)
		{
			resize(2 * capacity);
		}

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

	double pop()
	{
		double outputItem;
		outputItem = items[numItems - 1];
		numItems--;

		return outputItem;
	}

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

	//remove all items from stack
	void clear()
	{
		numItems = 0;
	}
};