//============================================================================
// Name        : BigInteger.cpp
// Author      : Oskar Pawica
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <stdio.h>
#include <string.h>

using namespace std;

class BigInteger
{
private:
	char* e;
	long size;

public:
	BigInteger() : e(NULL), size(0) {}
	BigInteger(long a){
		size = 1;
		if(a == 0)
		{
			e = new char[size];
			*e = '0';
		}
		else
		{
			size += numberOfDigits(abs(a));
			e = new char [size];
			if(a > 0)
				*e = '+';
			else {
				*e = '-';
				a = -a;
			}
			int i = 1;
			while(a >= 1)
			{
				sprintf(e+i, "%ld", a%10);
				a/=10;
				i++;
			}
		}
	}
	BigInteger(long ssize, bool): size(ssize), e(NULL) {}

	BigInteger(const char* a){
		size = 1;
		if(*a == '0'){
			e = new char [size];
			*e = '0';
		}
		else
		{
			char j;
			int i = 0;
			if(*a == '+' or *a == '-') {
				j = *a;
				i++;
			}
			else {
				j = '+';
			}
			while(*(a+i)>=48 and *(a+i)<=57) {
				size++;
				i++;
			}
			e = new char [size];
			*e = j;
			i--;
			int k = 1;
			while(*(a+i)>=48 and *(a+i)<=57) {
				*(e+k) = *(a+i);
				i--;
				k++;
			}
		}

	}

	virtual ~BigInteger()
	{
		delete [] e;
	}

	BigInteger (const BigInteger &b):size(b.size)
	{
		e = new char[b.size];
		strcpy(e, b.e);
	}

	BigInteger operator +(const BigInteger &b) const
	{
		if(e[0] == '0')
			return b;
		if(b.e[0] == '0')
			return *this;
		//if(e[0] == '-')
			//return b-(*this);
		//if(b.e[0] == '-')
			//return *this-b;
		if(b.e[0] == '-' and e[0] == '-')
			return -((*this)+b);

		BigInteger temp(this->size, true);
		temp.e = new char [this->size];
		temp.e[0] = '+';
		unsigned int i = 1;
		char temp_c;
		bool t = false;
		while (i <strlen(this->e) and i <strlen(b.e)) {
			temp_c = this->e[i]+b.e[i]-48;
			if(t) {
				temp_c+=1;
				t = false;
			}
			if(temp_c-48 > 10) {
				temp_c = (temp_c-48)%10;
				t = true;
			}
			temp.e[i] = temp_c;
			++i;
		}
		if (i<strlen(this->e)) {
			memcpy(temp.e+i, e+i, strlen(this->e)-i);

		}
		else if (i<strlen(this->e)) {
			memcpy(temp.e+i, b.e+i, strlen(b.e)-i);
		}
		if(t) {
			BigInteger temp2(this->size+1, true);
			strcpy(temp2.e, temp.e);
			temp2.e[size] = '1';
			return temp2;
		}
		else
			return temp;
	}

	BigInteger operator +(const long &a) const {
		BigInteger temp(a);
		return *this+a;
	}

	BigInteger operator +=(const BigInteger &b) {
		return *this+b;
	}

	BigInteger operator +=(const long &a) {
		return *this+a;
	}

/*
	BigInteger &operator *(const BigInteger &b)
	{
		BigInteger temp;
		temp = *this;
		delete [] e;
		e = new char [b.size+temp.size];

	}*/

	BigInteger operator -()
	{
		BigInteger temp(*this);
		if (*(this->e) == '-')
			temp.e[0] = '+';
		else if (*(this->e) == '+')
			temp.e[0] = '-';
		return temp;
	}

	BigInteger &operator =(const BigInteger &b)
	{
		size = b.size;
		delete [] e;
		e = new char [size];
		memcpy(e,b.e,size*sizeof(char));
		return *this;
	}

	char &operator [](const int b) {
		return e[size-1-b];
	}

	long numberOfDigits(long a) {

	    if(a<=9){
	        return 1;
	    }
	    return 1 + numberOfDigits(a/10);
	}

	friend ostream& operator <<(ostream& os, BigInteger& b);
	friend istream& operator >>(istream& is, BigInteger& b);
};

ostream& operator<<(ostream& os, BigInteger& b)
{
	if (*b.e == '0')
		os << '0';
	else{
		if (*b.e == '-')
			os << '-';
		for (int i = b.size-1; i > 0; i--)
			os << *(b.e+i);
	}
    return os;
}

/*istream& operator >>(istream& is, BigInteger& b)
{
}*/

int main() {
	long a = 150;
	char * b = "120";

	BigInteger bigint(a);
	BigInteger bigint2(b);
	BigInteger bigint3;
	bigint3 = (bigint+bigint2);
	cout<<"BI1: "<<bigint<<endl;
	cout<<"BI2: "<<bigint2<<endl;
	cout<<"BI3: "<<bigint3<<endl;
	cout<<"BI1 <- BI2"<<endl<<endl;

	bigint = bigint2;
	cout<<"BI1: "<<bigint<<endl;
	cout<<"BI2: "<<bigint2<<endl;
	bigint2 = -bigint2;
	cout<<"BI2: "<<bigint2<<endl;
	cout<<bigint2[1]<<endl;
	cout<<"KONIEC"<<endl;
	return 0;
}