#include<iostream>
using namespace std;

class managed_array {
	public:
		int* numbers;
		int numbers_held = 0;
		int capacity = 20;
		
		managed_array() {
			numbers = new int[20];
		}

		void add(int new_number) {
			if(numbers_held >= capacity){
				cout << "20 numbers reached, resizing to 40\n";
				int *old_numbers = numbers;
				numbers = new int[40];
				for(int i = 0; i < 20; i++)
					numbers[i] = old_numbers[i];
				delete [] old_numbers;
				capacity = 40;
			}
			numbers[numbers_held++] = new_number;
		}
		/* We'll add this next class */
		~managed_array() {
			delete [] numbers;
		}
};

int main(){
	managed_array am1;
	managed_array am2;

	am1.add(3);
	am1.add(5);
	am1.add(7);
	am1.add(9);

	for(int i = 0; i < 20; i++)
		am1.add(i);

	cout << "am1 is holding : " << am1.numbers_held << " numbers\n";
	for(int i = 0; i < am1.numbers_held; i++)
		cout << am1.numbers[i] << endl;
	return 0;
}