How do you find the iterator in the middle of two iterators?

Question

I\'m trying to convert my implementation of quicksort into a template that can be used with other containers besides a vector.

Originally I used indexes to find the

Answer 1

use:

http://www.cplusplus.com/reference/std/iterator/distance/

and

http://www.cplusplus.com/reference/std/iterator/advance/

Answer 2

std::distance can measure the distance between two iterators as efficiently as possible.

std::advance can increment an iterator as efficiently as possible.

I still wouldn't want to quicksort a linked list, though :)

Answer 3

To find middle iterator you should use:

first + (last - first) / 2

Answer 4

How about something like this?

bool isMovingFirst = true;
while(first != last) {
  if(isMovingFirst) {
    ++first;
  } else {
    --last;
  }
  isMovingFirst = !isMovingFirst;
}