multiset::erase
Removes an element or a range of elements in a multiset 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 multiset._First
Position of the first element removed from the multiset._Last
Position just beyond the last element removed from the multiset._Key
The key of the elements to be removed from the multiset.
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 multiset if no such element exists.
Note
This return type does not conform to the C++ standard.
For the third member function, returns the number of elements that have been removed from the multiset.
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.
// multiset_erase.cpp
// compile with: /EHsc
#include <set>
#include <iostream>
int main()
{
using namespace std;
multiset<int> ms1, ms2, ms3;
multiset<int>::iterator pIter, Iter1, Iter2;
int i;
multiset<int>::size_type n;
for (i = 1; i < 5; i++)
{
ms1.insert(i);
ms2.insert(i * i);
ms3.insert(i - 1);
}
// The 1st member function removes an element at a given position
Iter1 = ++ms1.begin();
ms1.erase(Iter1);
cout << "After the 2nd element is deleted, the multiset ms1 is:" ;
for (pIter = ms1.begin(); pIter != ms1.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 2nd member function removes elements
// in the range [_First, _Last)
Iter1 = ++ms2.begin();
Iter2 = --ms2.end();
ms2.erase(Iter1, Iter2);
cout << "After the middle two elements are deleted, "
<< "the multiset ms2 is:" ;
for (pIter = ms2.begin(); pIter != ms2.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 3rd member function removes elements with a given _Key
ms3.insert(2);
n = ms3.erase(2);
cout << "After the element with a key of 2 is deleted,\n"
<< "the multiset ms3 is:" ;
for (pIter = ms3.begin(); pIter != ms3.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 3rd member function returns the number of elements removed
cout << "The number of elements removed from ms3 is: "
<< n << "." << endl;
// The dereferenced iterator can also be used to specify a key
Iter1 = ++ms3.begin();
ms3.erase(Iter1);
cout << "After another element with a key"
<< endl;
cout << "equal to that of the 2nd element is deleted, "
<< "the multiset ms3 is:" ;
for (pIter = ms3.begin(); pIter != ms3.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
}
After the 2nd element is deleted, the multiset ms1 is: 1 3 4. After the middle two elements are deleted, the multiset ms2 is: 1 16. After the element with a key of 2 is deleted, the multiset ms3 is: 0 1 3. The number of elements removed from ms3 is: 2. After another element with a key equal to that of the 2nd element is deleted, the multiset ms3 is: 0 3.
Requirements
Header: <set>
Namespace: std