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Learn more about: logical_not Struct
logical_not Struct
11/04/2016
functional/std::logical_not
logical_not class
logical_not struct
892db678-31da-4540-974b-17b05efc0849

logical_not Struct

A predefined function object that performs the logical not operation (operator!) on its argument.

Syntax

template <classType = void> structlogical_not : publicunary_function<Type, bool> { booloperator()(const Type& Left) const; }; // specialized transparent functor for operator!template <> structlogical_not<void> { template <classType> autooperator()(Type&& Left) const -> decltype(!std::forward<Type>(Left)); };

Parameters

Type
Any type that supports an operator! that takes an operand of the specified or inferred type.

Left
The operand of the logical not operation. The unspecialized template takes an lvalue reference argument of type Type. The specialized template does perfect forwarding of lvalue and rvalue reference arguments of inferred type Type.

Return Value

The result of !Left. The specialized template does perfect forwarding of the result, which has the type that's returned by operator!.

Example

// functional_logical_not.cpp// compile with: /EHsc #include<deque> #include<algorithm> #include<functional> #include<iostream>intmain( ) { usingnamespacestd; deque<bool> d1, d2 ( 7 ); deque<bool>::iterator iter1, iter2; int i; for ( i = 0 ; i < 7 ; i++ ) { d1.push_back((bool)((i % 2) != 0)); } cout << boolalpha; // boolalpha I/O flag on cout << "Original deque:\n d1 = ( " ; for ( iter1 = d1.begin( ) ; iter1 != d1.end( ) ; iter1++ ) cout << *iter1 << ""; cout << ")" << endl; // To flip all the truth values of the elements,// use the logical_not function objecttransform( d1.begin( ), d1.end( ), d2.begin( ),logical_not<bool>( ) ); cout << "The deque with its values negated is:\n d2 = ( " ; for ( iter2 = d2.begin( ) ; iter2 != d2.end( ) ; iter2++ ) cout << *iter2 << ""; cout << ")" << endl; }
Original deque: d1 = ( false true false true false true false ) The deque with its values negated is: d2 = ( true false true false true false true )
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