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std::span::back(3)	       C++ Standard Libary	      std::span::back(3)

NAME
     std::span::back - std::span::back

Synopsis
	constexpr reference back() const;  (since C++20)

	Returns a reference to the last element in the span.

	Calling back on an empty span results in undefined behavior.

Parameters
	(none)

Return value
	A reference to the back element.

Complexity
	Constant.

Notes
	For a span c, the expression c.back() is equivalent to *(c.end() - 1).

Example
     // Run this code

      #include <iostream>
      #include <span>

      void print_forward(std::span<const int> const span)
      {
	  for (auto n{span.size()}; n != 0; --n)
	      std::cout << span.last(n).front() << ' ';
	  std::cout << '\n';
      }

      void print_backward(std::span<const int> const span)
      {
	  for (auto n{span.size()}; n != 0; --n)
	      std::cout << span.first(n).back() << ' ';
	  std::cout << '\n';
      }

      int main()
      {
	  constexpr int numbers[]{0, 1, 2, 3, 4};
	  print_forward(numbers);
	  print_backward(numbers);
      }

Output:
      0 1 2 3 4
      4 3 2 1 0

See also
	front access the first element
	      (public member function)

http://cppreference.com 	   2024.06.10		      std::span::back(3)
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