libstdc++
Negators
Collaboration diagram for Negators:

Classes

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

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 371 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 396 of file stl_function.h.