Mwahaha

evil.cpp

#include <stdio.h>
#include <float.h>
#include <math.h>
#include <algorithm>

int main()
{
    constexpr size_t count = 20;
    float vals[count] =
    {
        1.f, 2.f, 3.f, 4.f, NAN,
        1.f, 2.f, 3.f, 4.f, NAN,
        1.f, 2.f, 3.f, 4.f, NAN,
        1.f, 2.f, 3.f, 4.f, NAN,
    };
    //std::sort(vals, vals + count);
    //std::stable_sort(vals, vals + count);
    std::partial_sort(vals, vals + count, vals + count);

    for (size_t i = 0; i < count; ++i)
        printf("[%2d] %f\n", (int)i, vals[i]);

    return 0;
}