#include <iostream>

class VEC;

class VEC {
public:
	// default constructor
	VEC() {}

	// dimensions constructor
	VEC(int d) {
		dim = d;
		data = new double[d];
	}

	// copy constructor for &v
	VEC(const VEC &v) {
		std::cout << "\n Copy constructor (VEC) called!!";
		if (data)this->~VEC();
		dim = v.dim;
		data = v.data;
		if (data) memcpy((data = new double[dim]), v.data, sizeof(double) * dim);
	}

	// assignment constructor for &v
	void operator = (const VEC &v)
	{
		std::cout << "\n Assignment constructor (VEC &v) called!!";
		if (data)this->~VEC();
		dim = v.dim;
		data = v.data;
		if (data) memcpy((data = new double[dim]), v.data, sizeof(double) * dim);
	}

	// assignment constructor for v
	void operator = (const VEC v)
	{
		std::cout << "\n Assignment constructor (VEC v) called!!";
		if (data)this->~VEC();
		dim = v.dim;
		data = v.data;
		if (data) memcpy((data = new double[dim]), v.data, sizeof(double) * dim);
	}

	// destructor
	~VEC() {
		std::cout << "\n ~VEC got called. checking if data is true.";
		if (data) {
			std::cout << "\n data is true. attempting to delete data at address " << data;
			delete[] data;
			std::cout << "\n deletion succesful";
		}
		else std::cout << "\n data is false.";
	}

	// copy
	void copy(const VEC &v)
	{
		std::cout << "\n attempting to copy!";
		dim = v.dim;
		data = v.data;
		if (data) memcpy((data = new double[dim]), v.data, sizeof(double) * dim);
		std::cout << "\n Original (v.data)'s address == " << v.data;
		std::cout << "\n New (data)'s address == " << data;
		std::cout << "\n Copy operation successful! ";
	}
	int dim;
	double* data;
};

VEC Product(double x, VEC v) {
	int const dim = v.dim;
	VEC r(dim);
	for (int i = 0; i < v.dim; ++i) {
		r.data[i] = v.data[i] * x;
	}
	return VEC(r);
}

VEC EmptyVector(int n) {
	VEC r(n);
	std::cout << "\n empty vec start. \n vec address == " << &r << " and its data address == " << r.data;
	for (int i = 0; i < n; ++i) {
		r.data[i] = 0;
	}
	return VEC(r);
}

VEC UnitVector(int i, int n) {
	VEC r;
	std::cout << "\n unit vec start. \n vec address == " << &r << " and its data address == " << r.data;
	r.copy(EmptyVector(n));
	std::cout << "\n unit vec after copy. \n vec address == " << &r << " and its data address == " << r.data;
	r.data[i] = 1;
	return VEC(r);
}

int main() {
	std::cout << "\n attempting to calculate the gravity";
	VEC gravity = Product(5, UnitVector(1, 2));
	std::cout << "\n gravity vector calculation complete.";
	int pause = 0;
	std::cin >> pause;
	return 0;
}