set::erase
Removes an element or a range of elements in a set 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 set._First
Position of the first element removed from the set._Last
Position just beyond the last element removed from the set._Key
The key of the elements to be removed from the set.
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 set if no such element exists. For the third member function, the number of elements that have been removed from the set.
Note
This return type does not conform to the C++ standard.
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.
// set_erase.cpp
// compile with: /EHsc
#include <set>
#include <iostream>
int main()
{
using namespace std;
set<int> s1, s2, s3;
set<int>::iterator pIter, Iter1, Iter2;
int i;
set<int>::size_type n;
for (i = 1; i < 5; i++)
{
s1.insert(i);
s2.insert(i * i);
s3.insert(i - 1);
}
// The 1st member function removes an element at a given position
Iter1 = ++s1.begin();
s1.erase(Iter1);
cout << "After the 2nd element is deleted, the set s1 is:";
for (pIter = s1.begin(); pIter != s1.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 2nd member function removes elements
// in the range [_First, _Last)
Iter1 = ++s2.begin();
Iter2 = --s2.end();
s2.erase(Iter1, Iter2);
cout << "After the middle two elements are deleted, "
<< "the set s2 is:";
for (pIter = s2.begin(); pIter != s2.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 3rd member function removes elements with a given _Key
n = s3.erase(2);
cout << "After the element with a key of 2 is deleted, "
<< "the set s3 is:";
for (pIter = s3.begin(); pIter != s3.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
// The 3rd member function returns the number of elements removed
cout << "The number of elements removed from s3 is: "
<< n << "." << endl;
// The dereferenced iterator can also be used to specify a key
Iter1 = ++s3.begin();
s3.erase(*Iter1);
cout << "After another element (unique for set) with a key"
<< endl;
cout << "equal to that of the 2nd element is deleted, "
<< "the set s3 is:";
for (pIter = s3.begin(); pIter != s3.end(); pIter++)
cout << " " << *pIter;
cout << "." << endl;
}
After the 2nd element is deleted, the set s1 is: 1 3 4. After the middle two elements are deleted, the set s2 is: 1 16. After the element with a key of 2 is deleted, the set s3 is: 0 1 3. The number of elements removed from s3 is: 1. After another element (unique for set) with a key equal to that of the 2nd element is deleted, the set s3 is: 0 3.
Requirements
Header: <set>
Namespace: std