std::unordered_set<Key,Hash,KeyEqual,Allocator>::max_bucket_count
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std::unordered_set (C++17)
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unordered_set::max_bucket_count
(until C++20)
Deduction guides (C++17)
size_type max_bucket_count() const;
(since C++11)
Returns the maximum number of buckets the container is able to hold due to system or library implementation limitations.
[edit] Parameters
(none)
[edit] Return value
Maximum number of buckets.
[edit] Complexity
Constant.
[edit] Example
Run this code
#include <iostream> #include <unordered_set> int main() { struct Ha { std::size_t operator()(long x) const { return std::hash <long>{}(x); }; }; auto c1 = std::unordered_set <char>{}; auto c2 = std::unordered_set <long>{}; auto c3 = std::unordered_set <long, std::hash <int>>{}; auto c4 = std::unordered_set <long, Ha>{}; std::cout << "Max bucket count of\n" << std::hex << std::showbase << "c1: " << c1.max_bucket_count() << '\n' << "c2: " << c2.max_bucket_count() << '\n' << "c3: " << c3.max_bucket_count() << '\n' << "c4: " << c4.max_bucket_count() << '\n' ; }
Possible output:
Max bucket count of c1: 0xfffffffffffffff c2: 0xfffffffffffffff c3: 0xfffffffffffffff c4: 0xaaaaaaaaaaaaaaa