man Negation_functors (Fonctions bibliothèques) -

NAME

Negators -

Classes

class std::unary_negate< Predicate >

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

One of the negation functors.

Functions

template<class Predicate> unary_negate< Predicate > std::not1 (const Predicate &pred)

One of the negation functors. template<class Predicate> binary_negate< Predicate > std::not2 (const Predicate &pred)

One of the negation functors.

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]