Книга: Standard Template Library Programmer

Unique Hashed Associative Container

Unique Hashed Associative Container

Category: containers

Component type: concept

Description

A Unique Hashed Associative Container is a Hashed Associative Container that is also a Unique Associative Container. That is, it is a Hashed Associative Container with the property that no two elements in the container have the same key.

Refinement of

Hashed Associative Container, Unique Associative Container

Associated types

None, except for those described in the Hashed Associative Container and Unique Associative Container requirements.

Notation

X A type that is a model of Hashed Associative Container

a Object of type X

t Object of type X::value_type

k Object of type X::key_type

p, q Object of type X::iterator

nObject of type X::size_type

h Object of type X::hasher

c Object of type X::key_equal

Valid expressions

In addition to the expressions defined in Hashed Associative Container and Unique Associative Container, the following expressions must be valid.

Name Expression Type requirements Return type
Range constructor X(i, j)X a(i, j); i and j are Input Iterators whose value type is convertible to T [1]. X
Range constructor with bucket count X(i, j, n)X a(i, j, n); i and j are Input Iterators whose value type is convertible to T [1]. X
Range constructor with hash function X(i, j, n, h)X a(i, j, n, h); i and j are Input Iterators whose value type is convertible to T [1]. X
Range constructor with key equal X(i, j, n, h, k)X a(i, j, n, h, k); i and j are Input Iterators whose value type is convertible to T [1]. X

Expression semantics

Name Expression Precondition Semantics Postcondition
Range constructor X(i, j)X a(i, j); [i,j) is a valid range. Creates an associative container that contains all of the elements in the range [i,j) that have unique keys, using hasher() as the hash function and key_equal() as the key equality function. size() is less than or equal to the distance from i to j. The bucket count is an unspecified default value. The hash function is hasher(), and the key equality function is key_equal().
Range constructor with bucket count X(i, j, n)X a(i, j, n); [i,j) is a valid range. Creates an associative container that contains all of the elements in the range [i,j) that have unique keys, using at least n buckets, and using hasher() as the hash function and key_equal() as the key equality function. size() is less than or equal to the distance from i to j. The bucket count is greater than or equal to n. The hash function is hasher(), and the key equality function is key_equal().
Range constructor with hash function X(i, j, n, h)X a(i, j, n, h); [i,j) is a valid range. Creates an associative container that contains all of the elements in the range [i,j) that have unique keys, using at least n buckets, and using h as the hash function and key_equal() as the key equality function. size() is less than or equal to the distance from i to j. The bucket count is greater than or equal to n. The hash function is h, and the key equality function is key_equal().
Range constructor with key equal X(i, j, n, h, k) X a(i, j, n, h, k); [i,j) is a valid range. Creates an associative container that contains all of the elements in the range [i,j) that have unique keys, using at least n buckets, and using h as the hash function and k as the key equality function. size() is less than or equal to the distance from i to j. The bucket count is greater than or equal to n. The hash function is h , and the key equality function is k.

Complexity guarantees

The range constructor, range constructor with bucket count, range constructor with hash function, and range constructor with key equal, are all linear in j – i.

Models

• hash_set
• hash_map

Notes

[1] At present (early 1998), not all compilers support "member templates". If your compiler supports member templates then i and j may be of any type that conforms to the Input Iterator requirements. If your compiler does not yet support member templates, however, then i and j must be of type const T* or of type X::const_iterator.

See also

Associative Container, Hashed Associative Container, Multiple Hashed Associative Container Sorted Associative Container

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