std::ranges::split_view<V,Pattern>::begin - cppreference.com (original) (raw)

| constexpr /*iterator*/ begin(); | | (since C++20) | | --------------------------------- | | ------------- |

Returns an iterator to the first found subrange.

In order to provide the amortized constant time complexity required by the range concept, this function caches the result within the split_view (by means of _[cachedbegin](../split%5Fview.html#cached%5Fbegin "cpp/ranges/split view")_ member) for use on subsequent calls.

Let _[base](../split%5Fview.html#base "cpp/ranges/split view")_ be the underlying data member. Equivalent to:

constexpr /iterator/ begin() { if (!cached_begin_.has_value()) cached_begin_ = this->find_next(ranges::begin(base_)); return {*this, ranges::begin(base_), cached_begin_.value()}; }

[edit] Return value

An iterator.

[edit] Complexity

Amortized \(\scriptsize \mathcal{O}(1)\)O(1).

[edit] Example

Output:

begin(): "Keep" Substrings: "Keep" "moving" "forward" "" begin(): "K" Letters: K e e p . . m o v i n g . . f o r w a r d . .

[edit] See also

| | returns an iterator or a sentinel to the end (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns an iterator to the beginning (public member function of std::ranges::lazy_split_view<V,Pattern>) [edit] | | | returns an iterator to the beginning of a range(customization point object)[edit] |