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std::logical_not(3)	       C++ Standard Libary	     std::logical_not(3)

NAME
     std::logical_not - std::logical_not

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

	Function  object  for  performing logical NOT (logical negation). Effec-
     tively calls
	operator! for type T.

Specializations
	The standard library provides a specialization of std::logical_not
	when T is not specified, which leaves the parameter types and return
	type to be deduced.
									       (since
     C++14)
	logical_not<void> function object implementing !x deducing parameter
	(C++14) 	  and return types
			  (class template specialization)

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

	These	member	 types	 are   obtained    via	  publicly    inheriting
     (until C++11)
	std::unary_function<T, bool>.

Member functions
	operator() returns the logical NOT of the argument
		   (public member function)

     std::logical_not::operator()

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

	Returns the logical NOT of arg.

Parameters
	arg - value to compute logical NOT of

Return value
	The result of !arg.

Exceptions
	May throw implementation-defined exceptions.

Possible implementation
	constexpr // since C++14
	bool operator()(const T& arg) const
	{
	    return !arg;
	}

http://cppreference.com 	   2024.06.10		     std::logical_not(3)
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