CrackingTheCodeInterview-7.9.cpp

#include <iostream>
#include <stdexcept>

using namespace std;

template <class T> class CircularArray {
private:
	int size;
	int head;
	T* arr;

	int convert(int i) {
		return (head + i) % size;
	}

public:
	/* Constructor */
	CircularArray(int size) {
		if (size <= 0)
			throw std::invalid_argument( "illegal value" );

		arr = new T[size];
		head = 0;
		this->size = size;
	}

	/* Destructor */
	virtual ~CircularArray() {
		delete arr;
	}

	void shift(int shiftRight) {
		// TODO: neg input

		head = (head + shiftRight) % size;
	}

	T get(int i) {
		if (i < 0 || i >= size)
			throw std::invalid_argument( "illegal value" );
	
		return arr[convert(i)];
	}

	void set(int i, T t) {
		if (i < 0 || i >= size)
			throw std::invalid_argument( "illegal value" );
	
		arr[convert(i)] = t;
	}

	void print() {
		cout << "[";
		for (int i=0 ; i < size ; i++) {
			if (i)
				cout << ", ";
			cout << this->get(i);
		}
		cout << "]" << endl;
	}
};

int main() {
	int n = 10;
	CircularArray<int> cArr(n);

	// fill array
	for (int i=0 ; i < n ; i++) {
		cArr.set(i,i+1);
	}

	cArr.print();
	cArr.shift(3);
	cArr.print();
	cArr.shift(2);
	cArr.print();
}