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Returns the number of buckets in the unordered_multimap container.
A bucket is a slot in the container's internal hash table to which elements are assigned based on the hash value of their key.
The number of buckets influences directly the load factor of the container's hash table (and thus the probability of collision). The container automatically increases the number of buckets to keep the load factor below a specific threshold (its max_load_factor), causing a rehash each time the number of buckets needs to be increased.
Member type size_type is an unsigned integral type.
Possible output:
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
<unordered_map>
-
unordered_mapC++11
-
unordered_multimapC++11
unordered_multimap
-
unordered_multimap::~unordered_multimapC++11
-
unordered_multimap::unordered_multimapC++11
member functions
-
unordered_multimap::beginC++11
-
unordered_multimap::bucketC++11
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unordered_multimap::bucket_countC++11
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unordered_multimap::bucket_sizeC++11
-
unordered_multimap::cbeginC++11
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unordered_multimap::cendC++11
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unordered_multimap::clearC++11
-
unordered_multimap::countC++11
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unordered_multimap::emplaceC++11
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unordered_multimap::emplace_hintC++11
-
unordered_multimap::emptyC++11
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unordered_multimap::endC++11
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unordered_multimap::equal_rangeC++11
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unordered_multimap::eraseC++11
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unordered_multimap::findC++11
-
unordered_multimap::get_allocatorC++11
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unordered_multimap::hash_functionC++11
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unordered_multimap::insertC++11
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unordered_multimap::key_eqC++11
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unordered_multimap::load_factorC++11
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unordered_multimap::max_bucket_countC++11
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unordered_multimap::max_load_factorC++11
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unordered_multimap::max_sizeC++11
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unordered_multimap::operator=C++11
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unordered_multimap::rehashC++11
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unordered_multimap::reserveC++11
-
unordered_multimap::sizeC++11
-
unordered_multimap::swapC++11
-
non-member overloads
- Reference
- <unordered_map>
- unordered_multimap
- bucket_count
public member function
<unordered_map>
std::unordered_multimap::bucket_count
size_type bucket_count() const noexcept;
Return number of buckets
A bucket is a slot in the container's internal hash table to which elements are assigned based on the hash value of their key.
The number of buckets influences directly the load factor of the container's hash table (and thus the probability of collision). The container automatically increases the number of buckets to keep the load factor below a specific threshold (its max_load_factor), causing a rehash each time the number of buckets needs to be increased.
Parameters
noneReturn Value
The current amount of buckets.Member type size_type is an unsigned integral type.
Example
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Possible output:
myumm has 5 buckets. bucket #0 contains: [towel:bathroom] [towel:beach] bucket #1 contains: [plant:garden] bucket #2 contains: bucket #3 contains: bucket #4 contains: [oven:kitchen] [bed:bedroom] |
Complexity
Constant.Iterator validity
No changes.See also
- unordered_multimap::bucket
- Locate element's bucket (public member function)
- unordered_multimap::bucket_size
- Return bucket_size (public member type)
- unordered_multimap::load_factor
- Return load factor (public member function)
- unordered_multimap::max_bucket_count
- Return maximum number of buckets (public member function)
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