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std::ranges..._view::begin(3)  C++ Standard Libary std::ranges..._view::begin(3)

NAME
     std::ranges::common_view::begin - std::ranges::common_view::begin

Synopsis
	constexpr auto begin() requires (!__simple_view<V>);  (1) (since C++20)
	constexpr auto begin() const requires range<const V>; (2) (since C++20)

	1) Returns an iterator to the first element of the common_view, that is:
	  * ranges::begin(base_), if both ranges::random_access_range<V> and
	    ranges::sized_range<V> are satisfied,
	  * std::common_iterator<ranges::iterator_t<V>,
	    ranges::sentinel_t<V>>(ranges::begin(base_)) otherwise.
	Here  base_ (the name is for exposition only purposes) is the underlying
     view.
	2) Same as (1), but V is const-qualified.

Parameters
	(none)

Return value
	An iterator to the beginning of the underlying view.

Example
     // Run this code

      #include <iostream>
      #include <numeric>
      #include <ranges>
      #include <string_view>

      int main()
      {
	  constexpr auto 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

	Defect reports

	The following behavior-changing defect	reports  were  applied	retroac-
     tively 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

See also
	end	      returns an iterator to the end
	(C++20)       (public member function)
	ranges::begin returns an iterator to the beginning of a range
	(C++20)       (customization point object)
	ranges::end   returns a sentinel indicating the end of a range
	(C++20)       (customization point object)

http://cppreference.com 	   2024.06.10	   std::ranges..._view::begin(3)
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