class IntSet(){

	IntSet::IntSet(std::size_t max_elem)
	{
		:_nm(0)
		, _cp(max_elem)
		, _data((int *)malloc(_cp * sizeof(int)))
		assert(_data)
	}

	IntSet::~IntSet()
	{
		free(this->data)
	}

	IntSet::IntSet(const IntSet &other)
	{
		_nm = other._nm; //:_nm(other._nm)
		_cp = other._cp; //,_cp(other._cp)
		_data = (int *)std::malloc(_cp * sizeof(int));
		assert(_data);
		std::memcpy(_data, other._data, sizeof(int) * _nm);
	}

	IntSet::swap(IntSet &other)
	{
		using std::swap; //automatically destruct of copy (other), so free is not needed
		swap(_nm, _cp);
	}

	&IntSet IntSet::operator=(IntSet other)
	{
		swap(other);
		return *this;
	}


	//want to realize "<<" as adding operator

	&IntSet IntSet::operator<<(int elem)
	{
		assert(nm < _cp);
		_nm++;
		*(data + sizeof(int)) = elem;
		return *this;
	}

	//want to check if the element with value elem is in array


	bool IntSet::operator[](int elem)
	{
		for (std::size_t i = 0; i < _nm; i++)
		{
			if (_data[i] == elem)
			{
				return true;
			}
		}
		return false;
	}


	//want to check if A belongs to B

	bool IntSet::operator<=(const IntSet &other)
	{
		for (std::size_t i = 0; i < _nm; i++)
		{
			if (! other[_data[i]])
			{
				return false;
			}
		}
		return true;
	}


	//want to check if arrays are the same

	bool IntSet::operator==(const IntSet &other)
	{
		return *this<=other && other<=*this;
	}

	//want to