std::basic_string<CharT,Traits,Allocator>::empty
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< cpp | string | basic string
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std::basic_string
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basic_string::empty
(C++20)
(C++20)
(C++23)
(C++20)(C++20)
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
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(C++14)
(C++11)
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bool empty() const;
(noexcept since C++11) (constexpr since C++20)
Checks if the string has no characters, i.e. whether begin() == end().
[edit] Parameters
(none)
[edit] Return value
true if the string is empty, false otherwise
[edit] Complexity
Constant.
[edit] Example
Run this code
#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:''
[edit] See also
returns the number of characters that can be held in currently allocated storage
(public member function) [edit]
(public member function) [edit]