public member function

std::string::empty

bool empty() const noexcept;

Test if string is empty

Returns whether the string is empty (i.e. whether its length is 0).

This function does not modify the value of the string in any way. To clear the content of a string, see string::clear.

Parameters

none

Return Value

true if the string length is 0, false otherwise.

Example

// string::empty
#include <iostream>
#include <string>

int main ()
{
  std::string content;
  std::string line;
  std::cout << "Please introduce a text. Enter an empty line to finish:\n";
  do {
    getline(std::cin,line);
    content += line + '\n';
  } while (!line.empty());
  std::cout << "The text you introduced was:\n" << content;
  return 0;
}

This program reads the user input line by line and stores it into string content until an empty line is introduced.

Complexity

Unspecified, but generally constant.

Constant.

Iterator validity

No changes.

Data races

The object is accessed.

Exception safety

No-throw guarantee: this member function never throws exceptions.