std::unordered_map emplace_hint() method
- od C++11
// Non const version only
template <class... Args>
iterator emplace_hint( const_iterator hint, Args&&... args );
Inserts a new element to the container, using hint as a suggestion where the element should go. The element is constructed in-place, i.e. no copy or move operations are performed.
The constructor of the element type (value_type, that is, std::pair<const Key, T>
) is called with exactly the same arguments as supplied to the function, forwarded with std::forward<Args>(args)...
.
If rehashing occurs due to the insertion, all iterators are invalidated.
Otherwise iterators are not affected. References are not invalidated.
Rehashing occurs only if the new number of elements is greater than max_load_factor() * bucket_count()
.
Parameters
hint
- iterator, used as a suggestion as to where to insert the new elementargs
- arguments to forward to the constructor of the element
Return value
Returns an iterator to the newly inserted element. If the insertion failed because the element already exists, returns an iterator to the already existing element with the equivalent key.
Complexity
Average case, constant - O(1).
Worst case, linear in size of the container - O(size()).
Exceptions
If an exception is thrown by any operation, this function has no effect (strong exception guarantee).
Examples
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