Question

std::map find/end both provides const_iterator and iterator, e.g.

  iterator end ();
  const_iterator end () const

Out of curiosity,if I have a std::map , which will be called/compared here, an iterator or a const_iterator ? :

if(m.find(key) != m.end()) {
   ...
}

And should I care ?

Answer 1

If m is const, then a const_iterator will be returned; otherwise an iterator will be returned.

If all you are doing is testing for existence of an element in the map, then it doesn’t really matter which one is used.