#include <iostream>
#include <cstddef>

// Fixed‑string non‑type template parameter.
// Stores the characters of a literal at compile time.

template<std::size_t N>
struct fixed_string {
    char buf[N]{};
    // constexpr constructor copies characters.
    constexpr fixed_string(const char(&s)[N]) {
        for (std::size_t i = 0; i < N; ++i) buf[i] = s[i];
    }
    // constexpr size query.
    constexpr std::size_t size() const { return N; }
};

// Deduction guide from a string literal.
template<std::size_t N>
fixed_string(const char(&)[N]) -> fixed_string<N>;

// Example function taking a fixed_string NTTP.
template<fixed_string S>
void print_fixed() {
    std::cout << "fixed_string: " << S.buf << " (size=" << S.size() << ")" << std::endl;
}

int main() {
    print_fixed<"hello">();
    return 0;
}