CompileTimeFizzBuzz.cpp

#include <cstdio>

template <char... C>
struct S {
	static const char* value() {
		static constexpr char s[] = { C..., '\0' };
		return s;
	}
};

template <typename T, typename U>
struct Plus;

template <char... C, char... D>
struct Plus<S<C...>, S<D...>> {
	using Type = S<C..., D...>;
};

template <int N, char... C>
struct ToStr {
	using Type = typename ToStr<N/10, N%10+'0', C...>::Type;
};

template <char... C>
struct ToStr<0, C...> {
	using Type = S<C...>;
};

template <int I, int M = I%3, int N = I%5>
struct Value {
	using Type = typename ToStr<I>::Type;
};

template <int I, int N>
struct Value<I, 0, N> {
	using Type = S<'F','i','z','z'>;
};

template <int I, int M>
struct Value<I, M, 0> {
	using Type = S<'B','u','z','z'>;
};

template <int I>
struct Value<I, 0, 0> {
	using Type = S<'F','i','z','z','B','u','z','z'>;
};

template <int N>
struct FizzBuzz {
	using Type = typename Plus<
		typename FizzBuzz<N-1>::Type,
		typename Plus<
			typename Value<N>::Type,
			S<'\n'>
		>::Type
	>::Type;
};

template <>
struct FizzBuzz<0> {
	using Type = S<>;
};

int main() {
	puts(FizzBuzz<50>::Type::value());
}