Tidied up a little

     * checked for overflow problems before the type is converted back to the original type.

     */

    // std::enable_if<std::is_integral_v<T>>

    template <typename T, std::enable_if_t<!std::is_integral_v<T>, bool> = true> T Units::get(T inp, const std::string& str) {

        std::cout << "Input value: " << inp << std::endl;

    template <typename T, std::enable_if_t<!std::is_integral_v<T>, bool> = true>

    T Units::get(T inp, const std::string& str) {

        UnitType out = static_cast<UnitType>(inp) * get(str);

        std::cout << "Middle value: " << out << std::endl;

        if(out > static_cast<UnitType>(std::numeric_limits<T>::max()) ||

           out < static_cast<UnitType>(std::numeric_limits<T>::lowest())) {

            throw std::overflow_error("unit conversion overflows the type");

        }

        std::cout << "Output value 1: " << out << std::endl;

        std::cout << "Output value final: " << static_cast<T>(out) << std::endl;

        return static_cast<T>(out);

        //return out;

    }

    template <typename T, std::enable_if_t<std::is_integral_v<T>, bool> = true> T Units::get(T inp, const std::string& str) {

        std::cout << "Input value int: " << inp << std::endl;

        UnitType out = static_cast<UnitType>(inp) * get(str);

        std::cout << "Middle value int: " << out << std::endl;

        if(out > static_cast<UnitType>(std::numeric_limits<T>::max()) ||

           out < static_cast<UnitType>(std::numeric_limits<T>::lowest())) {

            throw std::overflow_error("unit conversion overflows the type");

        }

        std::cout << "--------------- Output value assert: " << out << ", " << static_cast<T>(out) << std::endl;

        if(out != static_cast<T>(out)) {

            throw std::invalid_argument("Cannot use integer value with non-integer internal unit; the combination " + std::to_string(inp) + " " + str + " is invalid.");

            throw std::invalid_argument("Cannot use integer value with non-integer internal unit; the combination " +

                                        std::to_string(inp) + " " + str + " is invalid.");

        }

        assert(out == static_cast<T>(out));

        //std::cout << "--------------- Output value assert: " << out << ", " << static_cast<T>(out) << std::endl;

        std::cout << "Output value 1 int: " << out << std::endl;

        std::cout << "Output value final int: " << static_cast<T>(out) << std::endl;

        return static_cast<T>(out);

    }