std::bitset::to_ullong(3)

NAME
std::bitset::to_ullong - std::bitset::to_ullong

Synopsis
   unsigned long long to_ullong() const (since C++11)
                        (constexpr since C++23)
   Converts the contents of the bitset to an unsigned long long integer.
   The first bit of the bitset corresponds to the least significant digit of the number
   and the last bit corresponds to the most significant digit.

Parameters
   (none)

Return value
   The converted integer

Exceptions
   std::overflow_error if the value can not be represented in unsigned long long.

Example
// Run this code
 #include <bitset>
 #include <iostream>
 #include <limits>
 int main()
 {
     std::bitset<std::numeric_limits<unsigned long long>::digits> b
     (
         0x123456789abcdef0LL
     );
     std::cout << b << " " << std::hex << b.to_ullong() << '\n';
     b.flip();
     std::cout << b << " " << b.to_ullong() << '\n';
     std::bitset<std::numeric_limits<unsigned long long>::digits + 1> q{0};
     try
     {
         (~q).to_ullong(); // throws
     }
     catch (const std::overflow_error& ex)
     {
         std::cout << "ex: " << ex.what() << '\n';
     }
 }

Output:
 0001001000110100010101100111100010011010101111001101111011110000 123456789abcdef0
 1110110111001011101010011000011101100101010000110010000100001111 edcba9876543210f
 ex: _Base_bitset::_M_do_to_ullong

See also
   to_string returns a string representation of the data
             (public member function)
   to_ulong returns an unsigned long integer representation of the data
             (public member function)