void helper_combinations(const int arr[], size_t size, unsigned k, std::string s)
{


	s += std::to_string(arr[0]);
	for (int i = 1; i <= size - k + 1; ++i)
	{
		//printArr(arr + i, size - i);
		//std::cout << "string : " << s << '\n';
		helper_combinations(arr + i, size - i, k - 1, s);
	}


	if (!k)
	{
		//std::cout << "arr " << (arr, size) << " ";
		std::cout << s << '\n';
		return;
	}
}

void combinations(const int arr[], size_t size, unsigned k)
{
	std::cout << "------ \n";

	if (size < k) return;

	std::string	temp = "";
	helper_combinations(arr, size, k, temp);

	combinations(arr + 1, size - 1, k);
}
int main()
{
	const int arr[] = { 1,2,3,4,5 };
	combinations(arr, 5, 1);
}