void remove_zeros()
	{
		if(big[1] == '0' && big_size > 2)
		{
			while(big[1] == '0')
			{
				BigInt tmp(big_size,1);
				tmp = *this;
				delete [] big;
				big_size = big_size-1;
				big = new char[big_size];
				big[0] = tmp.big[0];
				for (int i = big_size; i > 1; i--)
					big[i-1] = tmp.big[i];
			}
		}
	}