public member function

std::operator-

<iterator>
reverse_iterator operator- (difference_type n) const;
Subtraction operator
Returns a reverse iterator pointing to n elements before the element the object points to.

A global overload for operator- also exists for the case where one reverse_iterator object is subtracted from another one:
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template <class Iterator>
  typename reverse_iterator<Iterator>::difference_type operator- (
    const reverse_iterator<Iterator>& x,
    const reverse_iterator<Iterator>& y);

In this case, the function returns the difference between the two iterators (i.e., the number of elements between the elements pointed).

Parameters

n
Number of elements to offset.
difference_type is a member type defined as an alias of the base iterator's own difference type (generally, an integral type).

Return value

The reverse iterator itself (*this).

Example

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// reverse_iterator::operator- example
#include <iostream>
#include <iterator>
#include <vector>
using namespace std;

int main () {
  vector<int> myvector;
  for (int i=0; i<10; i++) myvector.push_back(i);	// myvector: 0 1 2 3 4 5 6 7 8 9

  typedef vector<int>::iterator iter_int;

  reverse_iterator<iter_int> rev_iterator;
  
  rev_iterator = myvector.rend() - 3;

  cout << "myvector.rend() points to : " << *rev_iterator << endl;

  return 0;
}


Output:

myvector.rend() points to: 2

See also