std::basic_string<CharT,Traits,Allocator>::empty (3) - Linux Manuals

std::basic_string<CharT,Traits,Allocator>::empty: std::basic_string<CharT,Traits,Allocator>::empty

NAME

std::basic_string<CharT,Traits,Allocator>::empty - std::basic_string<CharT,Traits,Allocator>::empty

Synopsis


bool empty() const; (until C++11)
bool empty() const noexcept; (since C++11)
                                            (until C++20)
[[nodiscard]] bool empty() const noexcept; (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


// 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:''

See also


       returns the number of characters
size (public member function)
length

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