std::map::emplace_hint

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 map container (the elements in a map always follow a specific order).
const_iterator is a member type, defined as a bidirectional iterator type that points to elements.

args

Arguments used to construct a new object of the mapped type for the inserted element.

Arguments forwarded to construct the new element (of type pair<const key_type, mapped_type>).
This can be one of:
- Two arguments: one for the key, the other for the mapped value.
- A single argument of a pair type with a value for the key as first member, and a value for the mapped value as second.
- piecewise_construct as first argument, and two additional arguments with tuples to be forwarded as arguments for the key value and for the mapped value respectivelly.
See pair::pair for more info.

Return value

Example

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// map::emplace_hint
#include <iostream>
#include <map>
int main ()
{
  std::map<char,int> mymap;
  auto it = mymap.end();
  it = mymap.emplace_hint(it,'b',10);
  mymap.emplace_hint(it,'a',12);
  mymap.emplace_hint(mymap.end(),'c',14);
  std::cout << "mymap contains:";
  for (auto& x: mymap)
    std::cout << " [" << x.first << ':' << x.second << ']';
  std::cout << '\n';
  return 0;
}

mymap contains: [a:12] [b:10] [c:14]

Complexity

Iterator validity

Data races

Exception safety

See also

map::emplace

Construct and insert element (public member function)

map::insert

Insert elements (public member function)

map::erase

Erase elements (public member function)