std:: negate

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C++
Utilities library
General utilities
Relational operators (deprecated in C++20)
Function objects
Function invocation
(C++17) (C++23)
Identity function object
(C++20)
Old binders and adaptors
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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.

(C++14)
function object implementing - x deducing parameter and return types
(class template specialization)
(since C++14)

Member types

Type Definition
result_type (deprecated in C++17) (removed in C++20) T
argument_type (deprecated in C++17) (removed in C++20) T

These member types are obtained via publicly inheriting std:: unary_function < T, T > .

(until C++11)

Member functions

operator()
returns the negation of the argument
(public member function)

std::negate:: operator()

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

Returns the negation of arg .

Parameters

arg - value to compute negation of

Return value

The result of - arg .

Exceptions

May throw implementation-defined exceptions.

Possible implementation 

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