Difference between revisions of "cpp/ranges/drop view"

Revision as of 23:29, 15 August 2022

drop_view models the concepts contiguous_range, random_access_range, bidirectional_range, forward_range, input_range, common_range, and sized_range when the underlying view V models respective concepts.

Expression-equivalent

Expression e is expression-equivalent to expression f, if

• e and f have the same effects, and
• either both are constant subexpressions or else neither is a constant subexpression, and
• either both are potentially-throwing or else neither is potentially-throwing (i.e. noexcept(e) == noexcept(f)).

Member functions

Deduction guides

Helper templates

This specialization of std::ranges::enable_borrowed_range makes drop_view satisfy borrowed_range when the underlying view satisfies it.

Example

#include <ranges>
#include <iostream>
 
int main()
{
    const auto nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 
    for (int i : nums | std::views::drop(2))
        std::cout << i << ' ';
    std::cout << '\n';
 
    for (int i : std::views::iota(1, 10) | std::views::drop(2))
        std::cout << i << ' ';
    std::cout << '\n';
 
    for (int i : std::ranges::drop_view{nums, 2})
        std::cout << i << ' ';
    std::cout << '\n';
}

3 4 5 6 7 8 9 
3 4 5 6 7 8 9 
3 4 5 6 7 8 9

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also