24 Ranges library [ranges]

24.7 Range adaptors [range.adaptors]

24.7.9 Drop while view [range.drop.while]

24.7.9.1 Overview [range.drop.while.overview]

Given a unary predicate pred and a view r, drop_­while_­view produces a view of the range [ranges​::​find_­if_­not(r, pred), ranges​::​end(r)).
Example
:
constexpr auto source = "  \t   \t   \t   hello there";
auto is_invisible = [](const auto x) { return x == ' ' || x == '\t'; };
auto skip_ws = drop_while_view{source, is_invisible};
for (auto c : skip_ws) {
  cout << c;                                    // prints hello there with no leading space
}
— end example
 ]