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std::counte...erator::base(3)  C++ Standard Libary std::counte...erator::base(3)

NAME
     std::counted_iterator::base - std::counted_iterator::base

Synopsis
	constexpr const I& base() const& noexcept; (1) (since C++20)
	constexpr I base() &&;			   (2) (since C++20)

	Returns the underlying base iterator.

	1) Returns a reference to the underlying iterator.
	2) Move constructs the return value from the underlying iterator.

Parameters
	(none)

Return value
	1) A reference to the underlying iterator.
	2) An iterator move constructed from the underlying iterator.

Exceptions
	May throw implementation-defined exceptions.

Example
     // Run this code

      #include <algorithm>
      #include <iostream>
      #include <iterator>
      #include <type_traits>
      #include <vector>

      int main()
      {
	  std::vector<int> v{0, 1, 2, 3, 4};

	  std::reverse_iterator<std::vector<int>::iterator> reverse{v.rbegin()};

	  std::counted_iterator counted{reverse, 3};

	  static_assert(std::is_same<
	      decltype(counted.base()),
	      std::reverse_iterator<std::vector<int>::iterator> const&
	  >{});

	  std::cout << "Print with reverse_iterator: ";
	  for (auto r = counted.base(); r != v.rend(); ++r)
	      std::cout << *r << ' ';
	  std::cout << '\n';

	  std::cout << "Print with counted_iterator: ";
	  for (; counted != std::default_sentinel; ++counted)
	      std::cout << counted[0] << ' ';
	  std::cout << '\n';
      }

Output:
      Print with reverse_iterator: 4 3 2 1 0
      Print with counted_iterator: 4 3 2

	Defect reports

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

	   DR	 Applied to	       Behavior as  published		    Cor-
     rect behavior
	LWG 3391 C++20	    the const version of base returns a copy of  returns
     a reference
			    the underlying iterator
	LWG  3593  C++20       the const version of base returns a	    made
     noexcept
			    reference but might not be noexcept

See also
	operator*  accesses the pointed-to element
	operator-> (public member function)
	(C++20)
	count	   returns the distance to the end
	(C++20)    (public member function)

http://cppreference.com 	   2024.06.10	   std::counte...erator::base(3)
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