fizzbuzz-unrolled.cpp

#include <boost/preprocessor.hpp>

#include <iostream>

template<int r> void print(int i) {
    if constexpr (r)
        if constexpr (r % 5)
            if constexpr (r % 3)
                std::cout << i << std::endl;
            else
                std::cout << "fizz" << std::endl;
        else
            std::cout << "buzz" << std::endl;
    else
        std::cout << "fizzbuzz" << std::endl;
}

void fizzbuzz(int min, int max) {
    int i = min;
    switch (min % 15) {
#define header(z, n, data) case n : i += 15 - n; break;
        BOOST_PP_REPEAT_FROM_TO(1, 15, header, _)
    }
    switch (min % 15) {
#define header2(z, n, data) case n : print<n>(min + n - 1);
        BOOST_PP_REPEAT_FROM_TO(1, 15, header2, _)
    }
    for (; i + 15 <= max; i += 15) {
#define body(z, n, data) print<n>(i + n);
        BOOST_PP_REPEAT_FROM_TO(0, 15, body, _)
    }
    switch (max - i) {
#define trailer2(z, n, data) print<n>(i + n);
#define trailer(z, r, data) case r : BOOST_PP_CAT(BOOST_PP_REPEAT_FROM_TO_, z)(0, BOOST_PP_INC(r), trailer2, _); break;
        BOOST_PP_REPEAT_FROM_TO(0, 15, trailer, _)
    }
}

int main() {
    fizzbuzz(1, 100);
}