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

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
 
bool empty() const;
(until C++11)
bool empty() const noexcept;
(since C++11)
(until C++20)
[[nodiscard]] constexpr bool empty() const noexcept;
(since C++20)

Checks if the string has no characters, i.e. whether begin() == end().

Contents

[edit] Parameters

(none)

[edit] Return value

true if the string is empty, false otherwise

[edit] Complexity

Constant.

[edit] 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:''

[edit] See also

returns the number of characters
(public member function) [edit]