std::bitset::size(3)

NAME
std::bitset::size - std::bitset::size

Synopsis
   std::size_t size() const; (noexcept since C++11)
                        (constexpr since C++11)
   Returns the number of bits that the bitset holds.

Parameters
   (none)

Return value
   number of bits that the bitset holds, i.e. the template parameter N.

Example
// Run this code
 #include <bitset>
 #include <iostream>
 int main()
 {
     std::cout << std::bitset<0x400>().size() << '\n';
 }

Output:
 1024

See also
   count returns the number of bits set to true
         (public member function)