std::negate

C++

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Defined in header <functional>
template< class T > struct negate;		(until C++14)
template< class T = void > struct negate;		(since C++14)

Function object for performing negation. Effectively calls operator- on an instance of type T.

Specializations

The standard library provides a specialization of std::negate when T is not specified, which leaves the parameter types and return type to be deduced. negate<void> function object implementing -x deducing argument and return types (class template specialization)

(since C++14)

Member types Type Definition result_type(deprecated in C++17) T argument_type(deprecated in C++17) T

(until C++20)

Member functions

operator()

returns the negation of the argument (public member function)

std::negate::operator()

T operator()( const T& arg ) const;		(until C++14)
constexpr T operator()( const T& arg ) const;		(since C++14)

Returns the negation of arg.

Parameters

arg

-

value to compute negation of

Return value

The result of -arg.

Exceptions

(none)

Possible implementation

constexpr T operator()(const T &arg) const { return -arg; }