[range.iter.op.advance] (original) (raw)

24 Iterators library [iterators]

24.4 Iterator primitives [iterator.primitives]

24.4.4 Range iterator operations [range.iter.ops]

24.4.4.2 ranges​::​advance [range.iter.op.advance]

Effects:

• Otherwise, if n is non-negative, incrementsi by n.
• Otherwise, decrements i by -n.

Effects:

• If I and S model assignable_from<I&, S>, equivalent to i = std​::​move(bound).
• Otherwise, if S and I model sized_sentinel_for<S, I>, equivalent to ranges​::​advance(i, bound - i).
• Otherwise, while bool(i != bound) is true, increments i.

Preconditions: If n > 0, [i, bound) denotes a range.

If n == 0, [i, bound) or [bound, i) denotes a range.

Effects:

• If S and I model sized_sentinel_for<S, I>:
  • If ​|n| ≥ |bound - i|, equivalent to ranges​::​advance(i, bound).
  • Otherwise, equivalent to ranges​::​advance(i, n).
• Otherwise,
  • if n is non-negative, while bool(i != bound) is true, increments i but at most n times.
  • Otherwise, while bool(i != bound) is true, decrements i but at most -n times.

Returns: n - M, where M is the difference between the ending and starting positions of i.