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ALINK="#ff0000">
unary_negate<AdaptablePredicate>
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Categories: functors, adaptors |
Component type: type |
Description
Unary_negate is a function object adaptor: it is an
Adaptable Predicate that represents the logical negation
of some other Adaptable Predicate. That is: if f is an
object of class unary_negate<AdaptablePredicate>, then
there exists an object pred of class AdaptablePredicate
such that f(x) always returns the same value as !pred(x). [1]
There is rarely any reason to construct a unary_negate
directly; it is almost always easier to use the helper function not1.
Example
Finds the first element in a list that does not lie in the range
from 1 to 10.
list<int> L;
...
list<int>::iterator in_range =
find_if(L.begin(), L.end(),
not1(compose2(logical_and<bool>(),
bind2nd(greater_equal<int>(), 1),
bind2nd(less_equal<int>(), 10))));
assert(in_range == L.end() || !(*in_range >= 1 && *in_range <= 10));
Definition
Defined in the standard header functional, and in the nonstandard
backward-compatibility header function.h.
Template parameters
Parameter
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Description
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Default
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AdaptablePredicate
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The type of the function object that this unary_negate is the logical
negation of.
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Model of
Adaptable Predicate
Type requirements
AdaptablePredicate must be a model of Adaptable Predicate.
Public base classes
unary_function<AdaptablePredicate::argument_type, bool>
Members
New members
These members are not defined in the
Adaptable Predicate
requirements, but are specific to
unary_negate.
Member
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Description
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unary_negate(const AdaptablePredicate& pred)
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The constructor. Creates a unary_negate<AdaptablePredicate>
whose underlying predicate is pred.
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template <class AdaptablePredicate>
unary_negate<AdaptablePredicate>
not1(const AdaptablePredicate& pred);
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If p is of type AdaptablePredicate then
not1(p) is equivalent to unary_negate<AdaptablePredicate>(p),
but more convenient. This is a global function, not a member
function.
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Notes
[1]
Strictly speaking, unary_negate is redundant. It can be
constructed using the function object logical_not and the
adaptor unary_compose.
See also
The function object overview, Adaptable Predicate, Predicate,
binary_negate, unary_compose, binary_compose
Copyright ©
1999 Silicon Graphics, Inc. All Rights Reserved.
TrademarkInformation
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