C 関数は他の関数内にネストできますか?

int main() {
  auto print_message = [](std::string message) {
    std::cout << message << "\n";
  };

  // Prints "Hello!" 10 times
  for (int i = 0; i < 10; i++) {
    print_message("Hello!");
  }
}

int main() {
  struct X {
    static void a() {}
    void b() {
      a();  // can call static member function inside non-static function.
    }
  };

  X::a(); // call the function from outside the class.

  X my_x;
  my_x.b(); // call the second function from outside the class.

  return 0;
}