public member function
<set>

std::multiset::emplace_hint

template <class... Args>
  iterator emplace_hint (const_iterator position, Args&&... args);
Construct and insert element with hint
Inserts a new element in the multiset, with a hint on the insertion position. This new element is constructed in place using args as the arguments for its construction.

This effectively increases the container size by one.

The value in position is used as a hint on the insertion point. The element will nevertheless be inserted at its corresponding position following the order described by its internal comparison object, but this hint is used by the function to begin its search for the insertion point, speeding up the process considerably when the actual insertion point is either position or close to it.

The element is constructed in-place by calling allocator_traits::construct with args forwarded.

There are no guarantees on the relative order of equivalent elements.
The relative ordering of equivalent elements is preserved, and newly inserted elements follow their equivalents already in the container.

Parameters

position
Hint for the position where the element can be inserted.
The function optimizes its insertion time if position points to the element that will follow the inserted element (or to the end, if it would be the last).
Notice that this does not force the new element to be in that position within the multiset container (the elements in a multiset always follow a specific order).
const_iterator is a member type, defined as a bidirectional iterator type that points to elements.
args
Arguments forwarded to construct the new element.

Return value

An iterator to the newly inserted element.

Member type iterator is a bidirectional iterator type that points to elements.

Example

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// multiset::emplace_hint
#include <iostream>
#include <set>
#include <string>

int main ()
{
  std::multiset<std::string> mymultiset;
  auto it = mymultiset.cbegin();

  mymultiset.emplace_hint (it,"apple");
  it = mymultiset.emplace_hint (mymultiset.cend(),"orange");
  it = mymultiset.emplace_hint (it,"melon");
  mymultiset.emplace_hint (it,"melon");

  std::cout << "mymultiset contains:";
  for (const std::string& x: mymultiset)
    std::cout << ' ' << x;
  std::cout << '\n';

  return 0;
}

Output:
mymultiset contains: apple melon melon orange

Complexity

Generally, logarithmic in the container size.
Amortized constant if the insertion point for the element is position.

Iterator validity

No changes.

Data races

The container is modified.
Concurrently accessing existing elements is safe, although iterating ranges in the container is not.

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the container.
If allocator_traits::construct is not supported with the appropriate arguments, it causes undefined behavior.

See also

  • 9281021542 2018-02-20
  • 632231541 2018-02-20
  • 9751491540 2018-02-20
  • 8333621539 2018-02-20
  • 995001538 2018-02-20
  • 6477441537 2018-02-20
  • 511981536 2018-02-19
  • 2072881535 2018-02-19
  • 6024461534 2018-02-19
  • 7594061533 2018-02-19
  • 9311341532 2018-02-19
  • 4928331531 2018-02-19
  • 38561530 2018-02-19
  • 7776611529 2018-02-19
  • 3038041528 2018-02-19
  • 9566341527 2018-02-19
  • 3936031526 2018-02-19
  • 9531111525 2018-02-19
  • 291211524 2018-02-19
  • 8962001523 2018-02-19