std::basic_string<CharT,Traits,Allocator>::empty
bool empty() const; |
(noexcept since C++11) (constexpr since C++20) |
Checks if the string has no characters, i.e. whether begin() == end().
Parameters
(none)
Return value
true if the string is empty, false otherwise
Complexity
Constant.
Example
#include <iostream>
#include <string>
int main()
{
std::string s;
std::boolalpha(std::cout);
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
s = "Exemplar";
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
s = "";
std::cout << "s.empty():" << s.empty() << "\t s:'" << s << "'\n";
}
Output:
s.empty():true s:'' s.empty():false s:'Exemplar' s.empty():true s:''
See also
| returns the number of characters (public member function) |
|
| returns the maximum number of characters (public member function) |
|
| returns the number of characters that can be held in currently allocated storage (public member function) |
|
|
(C++17)(C++20) | returns the size of a container or array (function template) |
|
(C++17) | checks whether the container is empty (function template) |
| checks whether the view is empty (public member function of std::basic_string_view<CharT,Traits>) |
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