public member function
<map>

std::map::find

      iterator find (const key_type& k);
const_iterator find (const key_type& k) const;
Get iterator to element
Searches the container for an element with a key equivalent to k and returns an iterator to it if found, otherwise it returns an iterator to map::end.

Two keys are considered equivalent if the container's comparison object returns false reflexively (i.e., no matter the order in which the elements are passed as arguments).

Another member function, map::count, can be used to just check whether a particular key exists.

Parameters

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

Return value

An iterator to the element, if an element with specified key is found, or map::end otherwise.

If the map 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 (of type value_type).
Notice that value_type in map containers is an alias of pair<const key_type, mapped_type>.

Example

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// map::find
#include <iostream>
#include <map>

int main ()
{
  std::map<char,int> mymap;
  std::map<char,int>::iterator it;

  mymap['a']=50;
  mymap['b']=100;
  mymap['c']=150;
  mymap['d']=200;

  it = mymap.find('b');
  if (it != mymap.end())
    mymap.erase (it);

  // print content:
  std::cout << "elements in mymap:" << '\n';
  std::cout << "a => " << mymap.find('a')->second << '\n';
  std::cout << "c => " << mymap.find('c')->second << '\n';
  std::cout << "d => " << mymap.find('d')->second << '\n';

  return 0;
}


Output:
elements in mymap:
a => 50
c => 150
d => 200

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

  • 9316991614 2018-02-25
  • 191841613 2018-02-25
  • 16411612 2018-02-25
  • 6081981611 2018-02-25
  • 1784561610 2018-02-25
  • 4651609 2018-02-25
  • 9348111608 2018-02-25
  • 2513771607 2018-02-25
  • 6478461606 2018-02-24
  • 4985791605 2018-02-24
  • 5637141604 2018-02-24
  • 282181603 2018-02-24
  • 6217941602 2018-02-24
  • 5076141601 2018-02-24
  • 714281600 2018-02-24
  • 6607141599 2018-02-24
  • 949041598 2018-02-24
  • 6809961597 2018-02-24
  • 671871596 2018-02-24
  • 7107821595 2018-02-24