#include <iostream>
#include <math.h>

using namespace std;

class Circle {
public:
	double radius;
	int x, y;
	Circle(double radius, int x, int y) {
		this->radius = radius;
		this->x = x;
		this->y = y;
	}
	Circle() {};
};

class CircleArray {
private:
	Circle * arr;
	int n;
	double *lengths;
	double PI = 3.14159265;
public:
	CircleArray(Circle *a, int n) {
		lengths = new double[n];
		for (int i = 0; i < n; i++) {
			lengths[i] = 2 * PI * a[i].radius;
		}
		this->n = n;
		arr = a;
	}

	~CircleArray() {
		delete lengths;
	}

	Circle& operator[] (int i) {
		return arr[i];
	};

	circleIterator& begin() {
		return circleIterator(this);
	}

	circleIterator& end() {
		circleIterator it(this);
		it.setCount = getSize();
		return it;
	}
	double *getLenghts() {
		return lengths;
	}

	int getSize() {
		return n;
	}

	Circle *getArray() {
		return arr;
	}
};

class circleIterator : public iterator<forward_iterator_tag, Circle> {
private:
	CircleArray * circleArray;
	int count;
	double PI = 3.14159265;
public:
	circleIterator(CircleArray *arr) {
		circleArray = arr;
		count = 0;
	}

	bool isEnd() {
		return count >= circleArray->getSize();
	}

	double operator* () {
		if (isEnd()) {
			throw "index out of range";
		}
		return circleArray->getLenghts()[count];
	}

	circleIterator& operator++ () {
		count++;
		return *this;
	}

	circleIterator& operator++ (int) {
		circleIterator temp(*this);
		operator++();
		return temp;
	}

	circleIterator& operator= (double newLen) {
		int i = getCount();
		circleArray->getLenghts()[i] = newLen;
		circleArray->getArray()[i].radius = newLen / (2 * PI);
		return *this;
	}

	int getCount() {
		return count;
	}

	void setCount(int n) {
		this->count = n;
	}
};