std::basic_string_view<CharT,Traits>::empty
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< cpp | string | basic string view
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std::basic_string_view
basic_string_view::empty
(C++20)
(C++20)
(C++23)
Constants
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Deduction guides (C++20)
constexpr bool empty() const noexcept;
(since C++17)
Checks if the view has no characters, i.e. whether size() == 0.
[edit] Parameters
(none)
[edit] Return value
true if the view is empty, false otherwise.
[edit] Complexity
Constant.
[edit] 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