Let E be an expression such that decltype((E)) is T, and let i be a dereferenceable object of type I.

I and T model output_iterator<I, T> only if *i++ = E; has effects equivalent to: *i = E; ++i;

Recommended practice: The implementation of an algorithm on output iterators should never attempt to pass through the same iterator twice; such an algorithm should be a single-pass algorithm.