constexpr duration operator+() const;
Returns: *this.
constexpr duration operator-() const;
Returns: duration(-rep_);.
Effects: ++rep_.
Returns: *this.
Returns: duration(rep_++);.
Effects: --rep_.
Returns: *this.
Returns: duration(rep_--);.
duration& operator+=(const duration& d);
Effects: rep_ += d.count().
Returns: *this.
duration& operator-=(const duration& d);
Effects: rep_ -= d.count().
Returns: *this.
duration& operator*=(const rep& rhs);
Effects: rep_ *= rhs.
Returns: *this.
duration& operator/=(const rep& rhs);
Effects: rep_ /= rhs.
Returns: *this.
duration& operator%=(const rep& rhs);
Effects: rep_ %= rhs.
Returns: *this.
duration& operator%=(const duration& rhs);
Effects: rep_ %= rhs.count().
Returns: *this.