std::unordered_multiset<Key,Hash,KeyEqual,Allocator>::begin, std::unordered_multiset<Key,Hash,KeyEqual,Allocator>::cbegin
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std::unordered_multiset unordered_multiset::beginunordered_multiset::cbegin
(C++23)
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(C++17)
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(until C++20)
Deduction guides (C++17)
iterator begin() noexcept;
(1)
(since C++11) (constexpr since C++26)
const_iterator begin() const noexcept;
(2)
(since C++11) (constexpr since C++26)
const_iterator cbegin() const noexcept;
(3)
(since C++11) (constexpr since C++26)
Returns an iterator to the first element of *this.
If *this is empty, the returned iterator will be equal to end() .
Contents
[edit] Return value
Iterator to the first element.
[edit] Complexity
Constant.
Notes
Because both iterator and const_iterator are constant iterators (and may in fact be the same type), it is not possible to mutate the elements of the container through an iterator returned by any of these member functions.
[edit] Example
Run this code
#include <iostream> #include <iterator> #include <string> #include <unordered_set> int main() { const std::unordered_multiset <std::string > words = { "some", "words", "to", "count", "count", "these", "words" }; for (auto it = words.begin(); it != words.end(); ) { auto count = words.count(*it); std::cout << *it << ":\t" << count << '\n'; std::advance (it, count); // all count elements have equivalent keys } }
Possible output:
some: 1 words: 2 to: 1 count: 2 these: 1
[edit] See also
(C++11)(C++14)
(function template) [edit]