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Negation_functors

NAME

Negators -

Classes

class std::binary_negate< _Predicate >
One of the negation functors.
class std::unary_negate< _Predicate >
One of the negation functors.

Functions

template<class _Predicate > unary_negate< _Predicate > std::not1 (const _Predicate &__pred)

template<class _Predicate > binary_negate< _Predicate > std::not2 (const _Predicate &__pred)

Detailed Description

The functions not1 and not2 each take a predicate functor and return an instance of unary_negate or binary_negate, respectively. These classes are functors whose operator() performs the stored predicate function and then returns the negation of the result.

For example, given a vector of integers and a trivial predicate,

   struct IntGreaterThanThree
     : public std::unary_function<int, bool>
   {
       bool operator() (int x) { return x > 3; }
   };
 
   std::find_if (v.begin(), v.end(), not1(IntGreaterThanThree()));
 
 

 The call to find_if will locate the first index (i) of v for which '!(v[i] > 3)' is true.

The not1/unary_negate combination works on predicates taking a single argument. The not2/binary_negate combination works on predicates which take two arguments.

Function Documentation

template<class _Predicate > unary_negate<_Predicate> std::not1 (const _Predicate & __pred) [inline]

One of the negation functors.

Definition at line 329 of file stl_function.h.

template<class _Predicate > binary_negate<_Predicate> std::not2 (const _Predicate & __pred) [inline]

One of the negation functors.

Definition at line 355 of file stl_function.h.

Author

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