c++ - What is the most effective way to get the index of an iterator of an std::vector? -

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i'm iterating on vector , need index iterator pointing at. afaik can done in 2 ways:

  • it - vec.begin()
  • std::distance(vec.begin(), it)

what pros , cons of these methods?

i prefer it - vec.begin() precisely opposite reason given naveen: wouldn't compile if change vector list. if during every iteration, end turning o(n) algorithm o(n^2) algorithm.

another option, if don't jump around in container during iteration, keep index second loop counter.


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