#include <iostream>

template<typename T>
class Array
{
private:
	int m_capacity = 0;
	T* m_data = nullptr;
public:
	Array(int capacity) : m_capacity(capacity), m_data(new T[capacity]{})
	{
	}

	~Array()
	{
		delete[] m_data;
	}

	T& operator[](int index)
	{
		return m_data[index];
	}

	friend std::ostream& operator<< (std::ostream& stream, const Array& array)
	{
		for (int i = 0; i <= array.m_capacity - 1; i++)
		{
			// how can i check in here if value under this key contains something that user set manually?
			stream << i << ": " << array.m_data[i] << std::endl;
		}
		return stream;
	}
};



int main()
{
	Array<int> test = Array<int>(5);
	test[0] = 1;
	test[1] = 0; // this 0 should be also displayed
	test[2] = 3;

	/*
	result right now:
	0: 1
	1: 0
	2: 3
	3: 0
	4: 0

	what i would like to achieve:
	0: 1
	1: 0
	2: 3

	so as you can see i would like to not display element 3,4 because i haven't set these values.
	*/
	std::cout << test << std::endl;
	std::getchar();
	return 0;
}