Coding Rules

#define SNAKE_CASE (1)

namespace snake_case {

//             east const
constexpr char const snake_case  = 0b00000010;

template <typename UpperCase>
class snake_case {
public:
    void snake_case();
private:
    int snake_case_; // underscore postfix
};

} // namespace snake_case

If condition has an else clause, condition should be positive.

// OK
#if defined(SOME_CONDITION)
    // do A
#else  // defined(SOME_CONDITION)
    // do B
#endif // defined(SOME_CONDITION)

// NG
#if !defined(SOME_CONDITION)
    // do B
#else  // !defined(SOME_CONDITION)
    // do A
#endif // !defined(SOME_CONDITION)