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[/
Copyright 2010 Neil Groves
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
/]
[section:lower_bound lower_bound]
[heading Prototype]
``
template<
class ForwardRange,
class Value
>
typename range_iterator<ForwardRange>::type
lower_bound(ForwardRange& rng, Value val);
template<
range_return_value re,
class ForwardRange,
class Value
>
typename range_return<ForwardRange, re>::type
lower_bound(ForwardRange& rng, Value val);
template<
class ForwardRange,
class Value,
class SortPredicate
>
typename range_iterator<ForwardRange>::type
lower_bound(ForwardRange& rng, Value val, SortPredicate pred);
template<
range_return_value re,
class ForwardRange,
class Value,
class SortPredicate
>
typename range_return<ForwardRange,re>::type
lower_bound(ForwardRange& rng, Value val, SortPredicate pred);
``
[heading Description]
The versions of `lower_bound` that return an iterator, returns the first iterator in the range `rng` such that:
without predicate - `*i < value` is `false`,
with predicate - `pred(*i, value)` is `false`.
`end(rng)` is returned if no such iterator exists.
The versions of `lower_bound` that return a `range_return`, defines `found` in the same manner as the returned iterator described above.
[heading Definition]
Defined in the header file `boost/range/algorithm/lower_bound.hpp`
[heading Requirements]
[*For the non-predicate versions:]
* `ForwardRange` is a model of the __forward_range__ Concept.
* `Value` is a model of the `LessThanComparableConcept`.
* The ordering of objects of type `Value` is a [*/strict weak ordering/], as defined in the `LessThanComparableConcept` requirements.
* `ForwardRange`'s value type is the same type as `Value`.
[*For the predicate versions:]
* `ForwardRange` is a model of the __forward_range__ Concept.
* `BinaryPredicate` is a model of the `StrictWeakOrderingConcept`.
* `ForwardRange`'s value type is the same type as `Value`.
* `ForwardRange`'s value type is convertible to both of `BinaryPredicate`'s argument types.
[heading Precondition:]
[*For the non-predicate versions:]
`rng` is sorted in ascending order according to `operator<`.
[*For the predicate versions:]
`rng` is sorted in ascending order according to `pred`.
[heading Complexity]
For ranges that model the __random_access_range__ concept the complexity is `O(log N)`, where `N` is `distance(rng)`.
For all other range types the complexity is `O(N)`.
[endsect]
|
