Negators(3)

NAME
Negators -

  Compounds
class binary_negate
One of the negation functors.
class unary_negate
One of the negation functors.

  Functions
template<class _Predicate> unary_negate< _Predicate > not1 (const _Predicate &__pred)
One of the negation functors.
template<class _Predicate> binary_negate< _Predicate > 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> not1 (const _Predicate & __pred) [inline]

One of the negation functors.

Definition at line 286 of file stl_function.h.

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

One of the negation functors.

Definition at line 311 of file stl_function.h.