public member function
<map>

std::multimap::upper_bound

      iterator upper_bound (const key_type& k);
const_iterator upper_bound (const key_type& k) const;
Return iterator to upper bound
Returns an iterator pointing to the first element in the container whose key is considered to go after k.

The function uses its internal comparison object (key_comp) to determine this, returning an iterator to the first element for which key_comp(k,element_key) would return true.

If the multimap class is instantiated with the default comparison type (less), the function returns an iterator to the first element whose key is greater than k.

A similar member function, lower_bound, has the same behavior as upper_bound, except in the case that the multimap contains elements with keys equivalent to k: In this case lower_bound returns an iterator pointing to the first of such elements, whereas upper_bound returns an iterator pointing to the element following the last.

Parameters

k
Key to search for.
Member type key_type is the type of the elements in the container, defined in multimap as an alias of its first template parameter (Key).

Return value

An iterator to the the first element in the container whose key is considered to go after k, or multimap::end if no keys are considered to go after k.

If the multimap object is const-qualified, the function returns a const_iterator. Otherwise, it returns an iterator.

Member types iterator and const_iterator are bidirectional iterator types pointing to elements.

Example

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// multimap::lower_bound/upper_bound
#include <iostream>
#include <map>

int main ()
{
  std::multimap<char,int> mymultimap;
  std::multimap<char,int>::iterator it,itlow,itup;

  mymultimap.insert(std::make_pair('a',10));
  mymultimap.insert(std::make_pair('b',121));
  mymultimap.insert(std::make_pair('c',1001));
  mymultimap.insert(std::make_pair('c',2002));
  mymultimap.insert(std::make_pair('d',11011));
  mymultimap.insert(std::make_pair('e',44));

  itlow = mymultimap.lower_bound ('b');  // itlow points to b
  itup = mymultimap.upper_bound ('d');   // itup points to e (not d)

  // print range [itlow,itup):
  for (it=itlow; it!=itup; ++it)
    std::cout << (*it).first << " => " << (*it).second << '\n';

  return 0;
}


b => 121
c => 1001
c => 2002
d => 11011

Complexity

Logarithmic in size.

Iterator validity

No changes.

Data races

The container is accessed (neither the const nor the non-const versions modify the container).
No mapped values are accessed: concurrently accessing or modifying elements is safe.

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the container.

See also

  • 997351548 2018-02-20
  • 903691547 2018-02-20
  • 9127171546 2018-02-20
  • 2234751545 2018-02-20
  • 1685381544 2018-02-20
  • 911091543 2018-02-20
  • 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