h

#include <iostream>
#include <vector>
#include <string>
#include <ostream>
#include <istream>

#ifndef BIGINTEGER_H
#define BIGINTEGER_H

class BigInteger {
public:
  BigInteger(std::string s);
  BigInteger();
  std::string toString();
  BigInteger(int x);
  BigInteger(std::vector<int> &a, bool sign);

  BigInteger operator- ();

  BigInteger& operator++();
  BigInteger& operator--();

  BigInteger operator++(int);
  BigInteger operator--(int);

  friend std::ostream& operator<<(std::ostream &os, const BigInteger& num);
  friend std::istream& operator>>(std::istream &is, BigInteger& num);

  friend bool operator== (const BigInteger& left, const BigInteger& right);
  friend bool operator!= (const BigInteger& left, const BigInteger& right);
  friend bool operator< (const BigInteger& left, const BigInteger& right);
  friend bool operator> (const BigInteger& left, const BigInteger& right);
  friend bool operator<= (const BigInteger& left, const BigInteger& right);
  friend bool operator>= (const BigInteger& left, const BigInteger& right);

  operator bool();

  friend BigInteger operator+ (const BigInteger& l, const BigInteger& r);
  friend BigInteger operator- (const BigInteger& l, const BigInteger& r);
  friend BigInteger operator* (const BigInteger& left, const BigInteger& right);
  friend BigInteger operator/ (const BigInteger& dividend, const BigInteger& divisor);
  friend BigInteger operator% (const BigInteger& left, const BigInteger& right);

  BigInteger& operator+= (const BigInteger& num);
  BigInteger& operator-= (const BigInteger& num);
  BigInteger& operator*= (const BigInteger& num);
  BigInteger& operator/= (const BigInteger& num);
  BigInteger& operator%= (const BigInteger& num);

  static void extend(std::vector<int>&a, int length);
  static std::vector<int> NaiveMultiplication(std::vector<int>& left, std::vector<int>& right);
  static std::vector<int> KaratsubaMultiplication(std::vector<int>&left, std::vector<int>& y);

private:
  int length;
  bool positive;
  std::vector<int> number;
};

#endif