std::basic_string_view::size,std::basic_string_view::length(3)

NAME
std::basic_string_view::size,std::basic_string_view::length - std::basic_string_view::size,std::basic_string_view::length

Synopsis
   constexpr size_type size() const noexcept; (since C++17)
   constexpr size_type length() const noexcept; (since C++17)
   Returns the number of CharT elements in the view, i.e. std::distance(begin(),
   end()).

Parameters
   (none)

Return value
   The number of CharT elements in the view.

Complexity
   Constant.

Example
// Run this code
 #include <iostream>
 #include <string_view>
 // Print a string surrounded by single quotes, its
 // length and whether it is considered empty.
 void check_string(std::string_view ref)
 {
     std::cout << std::boolalpha
               << "'" << ref << "' has " << ref.size()
               << " character(s); emptiness: " << ref.empty() << '\n';
 }
 int main(int argc, char **argv)
 {
     // An empty string
     check_string("");
     // Almost always not empty: argv[0]
     if (argc > 0)
         check_string(argv[0]);
 }

Possible output:
 '' has 0 character(s); emptiness: true
 './a.out' has 7 character(s); emptiness: false

See also
   empty checks whether the view is empty
            (public member function)
   max_size returns the maximum number of characters
            (public member function)
   size returns the number of characters
   length (public member function of std::basic_string<CharT,Traits,Allocator>)