Negators

Collaboration diagram for Negators:

Classes
class	std::binary_negate< _Predicate >
class	std::unary_negate< _Predicate >

Functions
template<typename _Predicate >
unary_negate< _Predicate >	std::not1 (const _Predicate &__pred)
template<typename _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<typename _Predicate >

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

inline

One of the negation functors.

Definition at line 718 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 743 of file stl_function.h.