std::bitset<N>::test (3) - Linux Manuals

std::bitset<N>::test: std::bitset<N>::test

NAME

std::bitset<N>::test - std::bitset<N>::test

Synopsis

bool test( size_t pos ) const;

Returns the value of the bit at the position pos.
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

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 <iostream>
  #include <bitset>

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

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

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

Output:

  first set bit at index 4