TIMER

#include <chrono>

struct TIMER final
{
    std::chrono::system_clock::time_point start, end;
    const char* str;
    TIMER(const char* s) : str(s)
    {
        start = std::chrono::system_clock::now();
    }

    ~TIMER()
    {
        end = std::chrono::system_clock::now();
        const double elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count();
        printf("%s: %f", str, elapsed);
    }
};