In this task, you are going to write a C++ class to handle very large numbers. The following prototype is given.
```cpp
class LLONG
{
public:
LLONG();
LLONG(int);
LLONG(const LLONG &);
~LLONG();
void add(const LLONG &);
void subtract(const LLONG &);
void multiply(const LLONG &);
void divide(const LLONG &);
void mod(const LLONG &);
std::ostream & output (std::ostream &);
int compare(const LLONG &);
// return 0 for equal, 1 for , -1 for <
private:
... // your design here
... // you are not allowed to use string here
};
```
