[#bsl-unordered_set-0d2d-2constructor-03c]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_set-0d2d.adoc[unordered_set]::unordered_set
:relfileprefix: ../../
:mrdocs:

Create an unordered set, and insert each `value_type` object in the sequence starting at the specified `first` element, and ending immediately before the specified `last` element, ignoring those keys having a value equivalent to that which appears earlier in the sequence. Optionally specify an `initialNumBuckets` indicating the initial size of the array of buckets of this container. If `initialNumBuckets` is not supplied, a single bucket is used. Optionally specify a `hashFunction` used to generate hash values for the keys contained in this set. If `hashFunction` is not supplied, a default‐constructed object of (template parameter) type `HASH` is used. Optionally specify a key‐equality functor `keyEqual` used to verify that two key values are the same. If `keyEqual` is not supplied, a default‐constructed object of (template parameter) type `EQUAL` is used. Optionally specify a `basicAllocator` used to supply memory. If `basicAllocator` is not supplied, a default‐constructed object of the (template parameter) type `ALLOCATOR` is used. If the type `ALLOCATOR` is `bsl::allocator` and `basicAllocator` is not supplied, the currently installed default allocator is used to supply memory. The (template parameter) type `INPUT_ITERATOR` shall meet the requirements of an input iterator defined in the C++11 standard [24.2.3]providing access to values of a type convertible to `value_type`, and `value_type` must be `emplace‐constructible` from `*i` into this unordered set, where `i` is a dereferenceable iterator in the range `[first .. last)]` (see {Requirements on `KEY`}). The behavior is undefined unless `first` and `last` refer to a sequence of valid values where `first` is at a position at or before `last`. Note that a `bslma::Allocator *` can be supplied for `basicAllocator` if the type `ALLOCATOR` is `bsl::allocator` (the default).

== Synopsis

Declared in `<bslstl_unorderedset.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class INPUT_ITERATOR>
unordered_set(
    INPUT_ITERATOR first,
    INPUT_ITERATOR last,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets = 0,
    HASH const& hashFunction = HASH(),
    EQUAL const& keyEqual = EQUAL(),
    ALLOCATOR const& basicAllocator = ALLOCATOR());
----


[.small]#Created with https://www.mrdocs.com[MrDocs]#