class UnknownSymbol: public LexError{
                        public:
                                const char symbol;
                                UnknownSymbol(const unsigned int lineNumber, symbol) :
                                        LexError(lineNumber), symbol(symbol) {};
                                virtual const char* what() const throw()
                                {
                                        std::string errorMessage;
                                        std::stringstream ss(std::stringstream::in
                                        | std::stringstream::out);

                                        ss << "Line " << lineNumber << ": Unknown Symbol detected: " << symbol;

                                        errorMessage = ss.str();
                                        return errorMessage.c_str();
                                }
                };