C++ Exception Class

I have to write/fix this class for an exception in a tic tac toe prompt game, it has to throw an error whenever 0>x>8

Any of you brilliant motherfuckers want to help?

#ifndef illegalmoveexception
#define illegalmoveexception

#include <stdexcept>
#include <string>

using namespace std;
class illegalmoveexception : public illegal_move_exception
{
public:
    illegalmoveexception();
    : illegal_move_exception("invalid move")
   
};

>>33
actually, it's more like:
I believe that there is some type of cat, however I don't believe in that we'll ever know whether or not there really is a cat, nor will we ever know the type of cat inside.