#include <iostream>
#include <cstdlib>   //for malloc and free
#include "obj.h"
using namespace std;

void *operator new[](size_t n);
void operator delete[](void *p);

int main()
{
	cout << "How many elements do you want to allocate? ";
	size_t n;
	cin >> n;

	int *const p1 = new int [n];   //calls operator new[] in line 48

	for (size_t i = 0; i < n; ++i) {
		cout << "The int at address " << p1 + i
			<< " holds " << p1[i] << ".\n";
	}

	cout << "The hidden numbers are "                          //unofficial
		<< reinterpret_cast<size_t *>(p1)[-2] << " and "
		<< reinterpret_cast<size_t *>(p1)[-1] << ".\n";

	delete[] p1;                   //calls operator delete[] in line 62

	cout << "\nAn obj is " << sizeof (obj) << " bytes, an array of " << n
		<< " of them is " << n * sizeof (obj)
		<< " bytes, and a size_t is " << sizeof (size_t) << " bytes.\n";

	obj *const p2 = new obj [n];   //calls operator new[] in line 48

	for (size_t i = 0; i < n; ++i) {
		cout << "The obj at address " << p2 + i
			<< " holds " << p2[i] << ".\n";
	}

	cout << "The hidden numbers are "
		<< reinterpret_cast<size_t *>(p2)[-3] << ", "
		<< reinterpret_cast<size_t *>(p2)[-2] << ", and "
		<< reinterpret_cast<size_t *>(p2)[-1] << ".\n";

	delete[] p2;                   //calls operator delete[] in line 62
	return EXIT_SUCCESS;
}

void *operator new[](size_t n)
{
	if (void *const p = malloc(n)) {
		cout << "operator new[](" << n << ") returns " << p
			<< " with hidden numbers "
			<< reinterpret_cast<size_t *>(p)[-2] << " and "
			<< reinterpret_cast<size_t *>(p)[-1] << ".\n";
		return p;
	}

	cerr << "operator new[](" << n << ") out of store.\n";
	exit(EXIT_FAILURE);
}

void operator delete[](void *p)
{
	cout << "operator delete[](" << p << ") with hidden numbers "
		<< reinterpret_cast<size_t *>(p)[-2] << " and "
		<< reinterpret_cast<size_t *>(p)[-1] << ".\n";

	free(p);
}