#include<iostream>
#include<string>
#include<sstream>
#include<cstdlib>
using namespace std;

class ma_iterator {
	int *spot;
	int remaining;
	public:
		ma_iterator(int *s, int r) : spot(s), remaining(r) {}
		int access(){
			return *spot;
		}
		int change(int newval){
			return *spot = newval;
		}
		bool iterate(){
			if(remaining){
				remaining--;
				spot++;
				return true;
			}
			return false;
		}
		bool done(){
			return remaining;
		}
};

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

		ma_iterator get_iterator(){
			return ma_iterator(numbers, numbers_held);
		}

		int access(int index){
			return numbers[index];
		}

		int modify(int index, int newvalue){
			numbers[index] = newvalue;
			return newvalue;
		}

		int search(int value){
			for(int i = 0; i < numbers_held; i++)
				if(numbers[i] == value)
					return i;
			return -1;
		}

		void remove(int index){
			numbers_held--;
			for(int i = index; i < numbers_held - 1; i++)
				numbers[i] = numbers[i+1];	
		}

		void map(void (*f)(int)){
			for(int i = 0; i < numbers_held; i++)
				f(numbers[i]);
		}

		string to_string_original(){
			char result[1024];
			int howfar = 0;
			howfar += sprintf(result, "[");
			for(int i = 0; i < numbers_held-1; i++){
				howfar += sprintf(result + howfar, "%d, ", numbers[i]);
			}
			howfar += sprintf(result+howfar, "%d]", numbers[numbers_held-1]);
			return string(result);
		}

		/* "c++ style" implementation using string streams
		 * I'd recommend this one for c++ programs in preference to the above
		 * Note that the above C-style will probably run faster, but will fail if
		 * the array doesn't fit in 1024 characters.  It'd be easy enough to allocate
		 * enough space above, something like numbers_held * 16.
		 */
		string to_string(){
			stringstream stream;
			stream << "[";
			for(int i = 0; i < numbers_held-1; i++)
				stream << numbers[i] << ", ";
			stream << numbers[numbers_held-1] << "]";
			return stream.str();
		}

		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;
		}
};

void print_number(int p){
	cout << p << endl;
}

int main(){
	managed_array am1;
	managed_array am2;

	am1.add(3);
	am1.add(5);
	am1.add(77);
	am1.add(9);
	am1.modify(0, 951);

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

	cout << "am1 is holding : " << am1.numbers_held << " numbers\n";
	am1.map(print_number);
	if(am1.search(77) != -1)
		cout << "77 is in the array\n";
	else
		cout << "77 is not in the array\n";

	am1.remove(2);


	cout << "After removing item 2, am1 is holding : " << am1.numbers_held << " numbers\n";
	am1.map(print_number);
	if(am1.search(77) != -1)
		cout << "77 is in the array\n";
	else
		cout << "77 is not in the array\n";

	cout << "Our array is:  " << am1.to_string() << endl;

	for(ma_iterator it = am1.get_iterator(); it.done(); it.iterate()){
		it.change(it.access() * 2);
	}

	cout << "Our array is:  " << am1.to_string() << endl;

	return 0;
}