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constexprauto begin() requires(!/*simple_view*/<V>); | (1) | (since C++20) |
constexprauto begin()const requires range<const V>; | (2) | (since C++20) |
common_view, that is:base_), if bothranges::random_access_range<V> andranges::sized_range<V> are satisfied,base_)) otherwise.V is const-qualified.Contents |
An iterator to the beginning of the underlying view.
#include <iostream>#include <numeric>#include <ranges>#include <string_view> int main(){constexprauto common= std::views::iota(1)| std::views::take(3)| std::views::common; for(int i{};int e: common)std::cout<<(i++?" + ":"")<< e; std::cout<<" = "<<std::accumulate(common.begin(), common.end(),0)<<'\n';}
Output:
1 + 2 + 3 = 6
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 4012 | C++20 | non-const overload missed simple-view check | added |
| returns an iterator to the end (public member function)[edit] | |
(C++20) | returns an iterator to the beginning of a range (customization point object)[edit] |
(C++20) | returns a sentinel indicating the end of a range (customization point object)[edit] |
