FizzBuzz.cpp

#include <iostream>
#include <utility>

#define Fizz(n) (n%3==0)
#define Buzz(n) (n%5==0)

template <char... Cs>
struct string_literal {
    constexpr static char value[] = {(Cs)..., 0};
};

template <size_t... digits>
struct to_chars {
    constexpr static auto value = string_literal<(digits+'0')..., '\n'>{};
};

template <size_t rem, size_t... digits>
struct to_string_literal : to_string_literal<rem / 10, rem % 10, digits...> {};

template <size_t... digits>
struct to_string_literal<0, digits...> : to_chars<digits...> {};

template <size_t n>
constexpr auto to_string_literal_v = to_string_literal<n>::value;

template <char... Cs1, char... Cs2>
constexpr auto operator+(string_literal<Cs1...> a, string_literal<Cs2...> b) {
    return string_literal<Cs1..., Cs2...>{};
}

template <class charT = char, charT... Cs>
constexpr auto operator""_S(){
    return string_literal<Cs..., '\n'>{};
}

template <size_t n>
constexpr auto FizzBuzz() {
    if constexpr (Fizz(n) && Buzz(n)) return "FizzBuzz"_S;
    else if constexpr (Fizz(n)) return "Fizz"_S;
    else if constexpr (Buzz(n)) return "Buzz"_S;
    else return to_string_literal_v<n>;
}

int main() {
    []<size_t... Vs>(std::index_sequence<Vs...>){
        std::cout << (FizzBuzz<Vs+1>() + ...).value;
    }(std::make_index_sequence<256>{});
}