std::basic_string_view<CharT,Traits>::empty
< cpp | string | basic string view
constexpr bool empty() const noexcept; |
(since C++17) (until C++20) |
|
[[nodiscard]] constexpr bool empty() const noexcept; |
(since C++20) | |
Checks if the view has no characters, i.e. whether size() == 0
.
Parameters
(none)
Return value
true if the view is empty, false otherwise
Complexity
Constant.
Example
Run this code
#include <string_view> #include <iostream> void check_string(std::string_view ref) { // Print a string surrounded by single quotes, its length // and whether it is considered empty. 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
returns the number of characters (public member function) | |
returns the maximum number of characters (public member function) |