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# std::chrono::treat_as_floating_point

From cppreference.com
< cpp‎ | chrono

Defined in header `<chrono>` |  |
template <class Rep> struct treat_as_floating_point : std::is_floating_point<Rep> {}; |  | (since C++11)

The `std::chrono::treat_as_floating_point` trait helps determine if a duration can be converted to another duration with a different tick period.

Implicit conversions between two durations normally depends on the tick period of the durations. However, implicit conversions can happen regardless of tick period if std::chrono::treat_as_floating_point<Rep>::value == true.

### [edit] Example

Run this code

    #include <iostream>
    #include <chrono>
    #include <thread>

    void timed_piece_of_code() {
        std::chrono::milliseconds simulated_work(2);
        std::this_thread::sleep_for(simulated_work);
    }

    int main() {

        auto start = std::chrono::high_resolution_clock::now();

        std::cout << "Running some timed piece of code..." << '\n';
        timed_piece_of_code();

        auto stop = std::chrono::high_resolution_clock::now();

        // A floating point milliseconds type
        typedef std::chrono::duration<float, std::chrono::milliseconds::period> fp_milliseconds;

        static_assert(
            std::chrono::treat_as_floating_point<fp_milliseconds::rep>::value,
            "Rep required to be floating point"
        );

        // Note that implicit conversion is not allowed here
        std::cout << "Time in milliseconds, using default rep: "
                  << std::chrono::duration_cast<std::chrono::milliseconds>(stop - start).count()
                  << '\n';

        // Note that implicit conversion is allowed here
        std::cout << "Time in milliseconds, using floating point rep: "
                  << fp_milliseconds(stop - start).count()
                  << '\n';

    }

Possible output:

    Running some timed piece of code...
    Timing stats:
      Time in milliseconds, using default rep: 2
      Time in milliseconds, using floating point rep: 2.57307

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