multimap::erase

Removes an element or a range of elements in a multimap from specified positions or removes elements that match a specified key.

iterator erase(
   iterator _Where
);
iterator erase(
   iterator _First,
   iterator _Last
);
size_type erase(
   const key_type& _Key
);

Parameters

• _Where
  Position of the element to be removed from the multimap.

• _First
  Position of the first element removed from the multimap.

• _Last
  Position just beyond the last element removed from the multimap.

• _Key
  The key of the elements to be removed from the multimap.

Return Value

For the first two member functions, a bidirectional iterator that designates the first element remaining beyond any elements removed, or a pointer to the end of the multimap if no such element exists.

For the third member function, returns the number of elements that have been removed from the multimap.

Remarks

In some instances, this method might throw an out_of_range exception.

Example

When compiling this example with the /Wp64 flag or on a 64-bit platform, compiler warning C4267 will be generated. For more information on this warning, see Compiler Warning (level 3) C4267.

// multimap_erase.cpp
// compile with: /EHsc
#include <map>
#include <iostream>

int main()
{
    using namespace std;
    multimap<int, int> m1, m2, m3;
    multimap<int, int> :: iterator pIter, Iter1, Iter2;
    int i;
    multimap<int, int>::size_type n;
    typedef pair<int, int> Int_Pair;

    for (i = 1; i < 5; i++)
    {
        m1.insert(Int_Pair (i, i) );
        m2.insert(Int_Pair (i, i*i) );
        m3.insert(Int_Pair (i, i-1) );
    }

    // The 1st member function removes an element at a given position
    Iter1 = ++m1.begin();
    m1.erase(Iter1);

    cout << "After the 2nd element is deleted, "
         << "the multimap ms1 is:";
    for (pIter = m1.begin(); pIter != m1.end(); pIter++)
        cout << " " << pIter -> second;
    cout << "." << endl;

    // The 2nd member function removes elements
    // in the range [_First, _Last)
    Iter1 = ++m2.begin();
    Iter2 = --m2.end();
    m2.erase(Iter1, Iter2);

    cout << "After the middle two elements are deleted, "
         << "the multimap m2 is:";
    for (pIter = m2.begin(); pIter != m2.end(); pIter++)
        cout << " " << pIter -> second;
    cout << "." << endl;

    // The 3rd member function removes elements with a given _Key
    m3.insert(Int_Pair (2, 5));
    n = m3.erase(2);

    cout << "After the element with a key of 2 is deleted,\n"
         << "the multimap m3 is:";
    for (pIter = m3.begin(); pIter != m3.end(); pIter++)
        cout << " " << pIter -> second;
    cout << "." << endl;

    // The 3rd member function returns the number of elements removed
    cout << "The number of elements removed from m3 is: "
         << n << "." << endl;

    // The dereferenced iterator can also be used to specify a key
    Iter1 = ++m3.begin();
    m3.erase(Iter1);

    cout << "After another element with a key equal to that"
         << endl;
    cout  << "of the 2nd element is deleted, "
          << "the multimap m3 is:";
    for (pIter = m3.begin(); pIter != m3.end(); pIter++)
        cout << " " << pIter -> second;
    cout << "." << endl;
}

After the 2nd element is deleted, the multimap ms1 is: 1 3 4.
After the middle two elements are deleted, the multimap m2 is: 1 16.
After the element with a key of 2 is deleted,
the multimap m3 is: 0 2 3.
The number of elements removed from m3 is: 2.
After another element with a key equal to that
of the 2nd element is deleted, the multimap m3 is: 0 3.

Requirements

Header: <map>

Namespace: std

See Also

Reference

multimap Class

Standard Template Library