Материал из C\C++ эксперт
force the vector to reallocate
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main( )
{
vector<int> v( 10, 66 );
v[1] = 100;
// get an iterator that points to the maximum
vector<int>::iterator before_itr = max_element( v.begin(), v.end() );
cout << "The maximum before resizing is " << *before_itr;
// make the index of the maximum
vector<int>::difference_type max_index = before_itr - v.begin();
// force the vector to reallocate
v.resize( v.capacity() + 1 );
}
