[/ 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:prev_permutation prev_permutation] [heading Prototype] `` template bool prev_permutation(BidirectionalRange& rng); template bool prev_permutation(const BidirectionalRange& rng); template bool prev_permutation(BidirectionalRange& rng, Compare pred); template bool prev_permutation(const BidirectionalRange& rng, Compare pred); `` [heading Description] `prev_permutation` transforms the range of elements `rng` into the lexicographically next smaller permutation of the elements if such a permutation exists. If one does not exist then the range is transformed into the lexicographically largest permutation and `false` is returned. `true` is returned when the next smaller permutation is successfully generated. The ordering relationship is determined by using `operator<` in the non-predicate versions, and by evaluating `pred` in the predicate versions. [heading Definition] Defined in the header file `boost/range/algorithm/permutation.hpp` [heading Requirements] [*For the non-predicate versions:] * `BidirectionalRange` is a model of the __bidirectional_range__ Concept. * `BidirectionalRange` is mutable. * `BidirectionalRange`'s value type is a model of the `LessThanComparableConcept`. * The ordering of objects of type `BidirectionalRange`'s value type is a [*/strict weak ordering/], as defined in the `LessThanComparableConcept` requirements. [*For the predicate versions:] * `BidirectionalRange` is a model of the __bidirectional_range__ Concept. * `BidirectionalRange` is mutable. * `Compare` is a model of the `StrictWeakOrderingConcept`. * `BidirectionalRange`'s value type is convertible to both of `Compare`'s argument types. [heading Complexity] Linear. At most `distance(rng) / 2` swaps. [endsect]