Negators
[Function Objects]

Collaboration diagram for Negators:

Classes

Functions


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

One of the negation functors.

Definition at line 364 of file stl_function.h.

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

One of the negation functors.

Definition at line 389 of file stl_function.h.


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