void erase ( iterator position );
size_type erase ( const key_type& x );
     void erase ( iterator first, iterator last );

Erase elements

Removes from the map container either a single element or a range of elements ([first,last)).

This effectively reduces the container size by the number of elements removed, calling each element's destructor.

Parameters

position

Iterator pointing to a single element to be removed from the map.
iterator is a member type, defined as a bidirectional iterator type.

x

Value to be removed from the map.
key_type is a member type defined in map containers as an alias of Key, which is the first template parameter and the type of the elements' keys.

first, last

Iterators specifying a range within the map container to be removed: [first,last). i.e., the range includes all the elements between first and last, including the element pointed by first but not the one pointed by last.

Return value

Example

// erasing from map
#include <iostream>
#include <map>
using namespace std;

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

  // insert some values:
  mymap['a']=10;
  mymap['b']=20;
  mymap['c']=30;
  mymap['d']=40;
  mymap['e']=50;
  mymap['f']=60;

  it=mymap.find('b');
  mymap.erase (it);                   // erasing by iterator

  mymap.erase ('c');                  // erasing by key

  it=mymap.find ('e');
  mymap.erase ( it, mymap.end() );    // erasing by range

  // show content:
  for ( it=mymap.begin() ; it != mymap.end(); it++ )
    cout << (*it).first << " => " << (*it).second << endl;

  return 0;
}

a => 10
d => 40

Complexity

See also