Function Test_example_KeepIf_performance

examples/readme_perf_examples.cpp:60–91

}

void Test_example_KeepIf_performance()
{
    using namespace fplus;

    typedef std::vector<int> Ints;
    auto run_loop = [&](const Ints values) {
        Ints odds;
        for (int x : values)
            if (is_odd_int(x))
                odds.push_back(x);
        return odds;
    };
    auto run_stl = [&](const Ints values) {
        Ints odds;
        std::copy_if(std::begin(values), std::end(values),
            std::back_inserter(odds), is_odd_int);
        return odds;
    };
    auto run_FunctionalPlus = [&](const Ints values) { return keep_if(is_odd_int, values); };

    // make debug runs faster
#if defined NDEBUG || defined _DEBUG
    std::size_t numRuns = 10;
#else
    std::size_t numRuns = 20000;
#endif

    Ints values = generate<Ints>(rand, 5000);
    run_n_times(run_loop, numRuns, "Hand-written for loop", values);
    run_n_times(run_stl, numRuns, "std::copy_if", values);
    run_n_times(run_FunctionalPlus, numRuns, "FunctionalPlus::keep_if", values);
}

int main()
{