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std::bitset::test(3)	       C++ Standard Libary	    std::bitset::test(3)

NAME
     std::bitset::test - std::bitset::test

Synopsis
	bool test( std::size_t pos ) const;  (constexpr since C++23)

	Returns the value of the bit at the position pos (counting from 0).

	Unlike	operator[], performs a bounds check and throws std::out_of_range
     if pos does
	not correspond to a valid position in the bitset.

Parameters
	pos - position of the bit to return (counting from 0)

Return value
	true if the requested bit is set, false otherwise.

Exceptions
	std::out_of_range if pos does not correspond to a valid position  within
     the bitset.

Example
     // Run this code

      #include <bit>
      #include <bitset>
      #include <cassert>
      #include <iostream>
      #include <stdexcept>

      int main()
      {
	  std::bitset<10> b1("1111010000");

	  std::size_t idx = 0;
	  while (idx < b1.size() && !b1.test(idx))
	      ++idx;

	  assert(static_cast<int>(idx) == std::countr_zero(b1.to_ulong()));

	  if (idx < b1.size())
	      std::cout << "The first set bit is at index " << idx << '\n';
	  else
	      std::cout << "no set bits\n";

	  try
	  {
	      std::bitset<0B10'1001'1010> bad;
	      if (bad.test(bad.size()))
		  std::cout << "Expect unexpected!\n";
	  }
	  catch (std::out_of_range const& ex)
	  {
	      std::cout << "Exception: " << ex.what() << '\n';
	  }
      }

Possible output:
      The first set bit is at index 4
      Exception: bitset::test: __position (which is 666) >= _Nb (which is 666)

See also
	operator[]     accesses specific bit
		       (public member function)
	popcount       counts the number of 1 bits in an unsigned integer
	(C++20)        (function template)
	has_single_bit checks if a number is an integral power of 2
	(C++20)        (function template)

http://cppreference.com 	   2024.06.10		    std::bitset::test(3)
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