The library provides basic function object classes for all of the arithmetic operators in the language ([expr.mul], [expr.add]).
template <class T = void> struct plus {
constexpr T operator()(const T& x, const T& y) const;
typedef T first_argument_type;
typedef T second_argument_type;
typedef T result_type;
};
operator() returns x + y.
template <class T = void> struct minus {
constexpr T operator()(const T& x, const T& y) const;
typedef T first_argument_type;
typedef T second_argument_type;
typedef T result_type;
};
operator() returns x - y.
template <class T = void> struct multiplies {
constexpr T operator()(const T& x, const T& y) const;
typedef T first_argument_type;
typedef T second_argument_type;
typedef T result_type;
};
operator() returns x * y.
template <class T = void> struct divides {
constexpr T operator()(const T& x, const T& y) const;
typedef T first_argument_type;
typedef T second_argument_type;
typedef T result_type;
};
operator() returns x / y.
template <class T = void> struct modulus {
constexpr T operator()(const T& x, const T& y) const;
typedef T first_argument_type;
typedef T second_argument_type;
typedef T result_type;
};
operator() returns x % y.
template <class T = void> struct negate {
constexpr T operator()(const T& x) const;
typedef T argument_type;
typedef T result_type;
};
operator() returns -x.
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));
typedef unspecified is_transparent;
};
operator() returns std::forward<T>(t) + std::forward<U>(u).
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));
typedef unspecified is_transparent;
};
operator() returns std::forward<T>(t) - std::forward<U>(u).
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));
typedef unspecified is_transparent;
};
operator() returns std::forward<T>(t) * std::forward<U>(u).
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));
typedef unspecified is_transparent;
};
operator() returns std::forward<T>(t) / std::forward<U>(u).
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));
typedef unspecified is_transparent;
};
operator() returns std::forward<T>(t) % std::forward<U>(u).
template <> struct negate<void> {
template <class T> constexpr auto operator()(T&& t) const
-> decltype(-std::forward<T>(t));
typedef unspecified is_transparent;
};
operator() returns -std::forward<T>(t).