RetroSearch Browse

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://en.cppreference.com/w/cpp/language/../string/../ranges/approximately_sized_range.html below:

std::ranges::approximately_sized_range - cppreference.com

template< class T > concept approximately_sized_range = ranges::range<T> && requires(T& t) { ranges::reserve_hint(t); }; (since C++26)

The approximately_sized_range concept specifies the requirements of a range type that can estimate its size in constant time with the reserve_hint function.

[edit] Semantic requirements

Given an lvalue t of type std::remove_reference_t<T>, T models approximately_sized_range only if

ranges::reserve_hint(t)

has amortized constant-time complexity,
does not alter the value of t in a manner observable to equality-preserving expressions, and
has a value that is not negative and is representable in ranges::range_difference_t<T>, and

if ranges::iterator_t<T> models forward_iterator, ranges::reserve_hint(t) is well-defined regardless of the evaluation of ranges::begin(t) (in other words, a single-pass approximately sized range may support a call to reserve_hint only before the first call to begin, but a forward range must support size at all times).

[edit] Notes [edit] Example [edit] See also

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4