| [section:binary_search binary_search] |
| |
| [heading Prototype] |
| |
| `` |
| template<class ForwardRange, class Value> |
| bool binary_search(const ForwardRange& rng, const Value& val); |
| |
| template<class ForwardRange, class Value, class BinaryPredicate> |
| bool binary_search(const ForwardRange& rng, const Value& val, BinaryPredicate pred); |
| `` |
| |
| [heading Description] |
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| `binary_search` returns `true` if and only if the value `val` exists in the range `rng`. |
| |
| [heading Definition] |
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| Defined in the header file `boost/range/algorithm/binary_search.hpp` |
| |
| [heading Requirements] |
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| [*For the non-predicate versions of binary_search:] |
| |
| * `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 of binary_search:] |
| |
| * `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 `BinaryPredicate`'s argument type. |
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| [heading Precondition:] |
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| [*For the non-predicate version:] |
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| `rng` is ordered in ascending order according to `operator<`. |
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| [*For the predicate version:] |
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| `rng` is ordered in ascending order according to the function object `pred`. |
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| [heading Complexity] |
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| For non-random-access ranges, the complexity is `O(N)` where `N` is `distance(rng)`. |
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| For random-access ranges, the complexity is `O(log N)` where `N` is `distance(rng)`. |
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| [endsect] |
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