[#bsl-unordered_map-0bf-2constructor-042]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_map-0bf.adoc[unordered_map<basic_string<char>, Json, TransparentHash, TransparentEqualTo>]::unordered_map
:relfileprefix: ../../
:mrdocs:

Create an empty unordered map having a `max_load_factor` of 1.0. Optionally specify an `initialNumBuckets` indicating the minimum initial size of the array of buckets of this unordered map. If `initialNumBuckets` is not supplied, one empty bucket shall be used and no memory allocated. Optionally specify a `hashFunction` used to generate the hash values associated with the `KEY‐VALUE` pairs contained in this unordered map. If `hashFunction` is not supplied, a default‐constructed object of the (template parameter) type `HASH` is used. Optionally specify a key‐equality functor `keyEqual` used to determine whether two keys are equivalent. If `keyEqual` is not supplied, a default‐constructed object of the (template parameter) type `EQUAL` is used. Optionally specify the `basicAllocator` used to supply memory. If `basicAllocator` is not supplied, a default‐constructed object of the (template parameter) type `ALLOCATOR` is used. If the `ALLOCATOR` type is `bsl::allocator` (the default), then `basicAllocator` shall be convertible to `bslma::Allocator *`. If the `ALLOCATOR` type is `bsl::allocator` and `basicAllocator` is not supplied, the currently installed default allocator is used to supply memory. Note that more than `initialNumBuckets` buckets may be created in order to preserve the bucket allocation strategy of the hash‐table (but never fewer).

== Synopsis

Declared in `<bslstl_unorderedmap.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
explicit
unordered_map(
    xref:bsl/unordered_map-0bf/size_type.adoc[size_type] initialNumBuckets,
    xref:BloombergLP/bdlb/TransparentHash.adoc[TransparentHash] const& hashFunction = HASH(),
    xref:BloombergLP/bdlb/TransparentEqualTo.adoc[TransparentEqualTo] const& keyEqual = EQUAL(),
    xref:bsl/allocator-0df.adoc[allocator<pair<basic_string<char> const, Json>>] const& basicAllocator = ALLOCATOR());
----


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