#include <benchmark/benchmark.h>

int fib1(int n)
{
    if (n < 2)
        return n;
    else
        return fib1(n - 1) + fib1(n - 2);
}

int fib2(int n)
{
    if (n < 2)
        return n;
    else
        return fib2(n - 2) + fib2(n - 1);
}

int fib3(int n)
{
    return n < 2 ? n : fib3(n - 1) + fib3(n - 2);
}

int fib4(int n)
{
    return n < 2 ? n : fib4(n - 2) + fib4(n - 1);
}

template<auto f> static void test(benchmark::State &state)
{
    int n = 0;
    for (auto _: state)
        benchmark::DoNotOptimize(f(n++ & 31));
}

BENCHMARK(test<fib1>)->Iterations(10'000);
BENCHMARK(test<fib2>)->Iterations(10'000);
BENCHMARK(test<fib3>)->Iterations(10'000);
BENCHMARK(test<fib4>)->Iterations(10'000);

BENCHMARK_MAIN();