23 General utilities library [utilities]

23.14 Function objects [function.objects]

23.14.6 Arithmetic operations [arithmetic.operations]

The library provides basic function object classes for all of the arithmetic operators in the language ([expr.mul], [expr.add]).

23.14.6.1 Class template plus [arithmetic.operations.plus]

template<class T = void> struct plus { constexpr T operator()(const T& x, const T& y) const; };
constexpr T operator()(const T& x, const T& y) const;
Returns: x + y.
template<> struct plus<void> { template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) + std::forward<U>(u)); using is_transparent = unspecified; };
template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) + std::forward<U>(u));
Returns: std​::​forward<T>(t) + std​::​forward<U>(u).

23.14.6.2 Class template minus [arithmetic.operations.minus]

template<class T = void> struct minus { constexpr T operator()(const T& x, const T& y) const; };
constexpr T operator()(const T& x, const T& y) const;
Returns: x - y.
template<> struct minus<void> { template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) - std::forward<U>(u)); using is_transparent = unspecified; };
template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) - std::forward<U>(u));
Returns: std​::​forward<T>(t) - std​::​forward<U>(u).

23.14.6.3 Class template multiplies [arithmetic.operations.multiplies]

template<class T = void> struct multiplies { constexpr T operator()(const T& x, const T& y) const; };
constexpr T operator()(const T& x, const T& y) const;
Returns: x * y.
template<> struct multiplies<void> { template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) * std::forward<U>(u)); using is_transparent = unspecified; };
template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) * std::forward<U>(u));
Returns: std​::​forward<T>(t) * std​::​forward<U>(u).

23.14.6.4 Class template divides [arithmetic.operations.divides]

template<class T = void> struct divides { constexpr T operator()(const T& x, const T& y) const; };
constexpr T operator()(const T& x, const T& y) const;
Returns: x / y.
template<> struct divides<void> { template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) / std::forward<U>(u)); using is_transparent = unspecified; };
template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) / std::forward<U>(u));
Returns: std​::​forward<T>(t) / std​::​forward<U>(u).

23.14.6.5 Class template modulus [arithmetic.operations.modulus]

template<class T = void> struct modulus { constexpr T operator()(const T& x, const T& y) const; };
constexpr T operator()(const T& x, const T& y) const;
Returns: x % y.
template<> struct modulus<void> { template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) % std::forward<U>(u)); using is_transparent = unspecified; };
template<class T, class U> constexpr auto operator()(T&& t, U&& u) const -> decltype(std::forward<T>(t) % std::forward<U>(u));
Returns: std​::​forward<T>(t) % std​::​forward<U>(u).

23.14.6.6 Class template negate [arithmetic.operations.negate]

template<class T = void> struct negate { constexpr T operator()(const T& x) const; };
constexpr T operator()(const T& x) const;
Returns: -x.
template<> struct negate<void> { template<class T> constexpr auto operator()(T&& t) const -> decltype(-std::forward<T>(t)); using is_transparent = unspecified; };
template<class T> constexpr auto operator()(T&& t) const -> decltype(-std::forward<T>(t));
Returns: -std​::​forward<T>(t).