public member function

std::basic_string::back

      charT& back();const charT& back() const;

Access last character

Returns a reference to the last character of the basic_string.

This function shall not be called on empty strings.

Parameters

none

Return value

A reference to the last character in the basic_string.

If the basic_string object is const-qualified, the function returns a

const charT&. Otherwise, it returns a charT&.charT is basic_string's character type (i.e., its first template parameter).

Example

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

int main ()
{
  std::string str ("hello world.");
  str.back() = '!';
  std::cout << str << '\n';
  return 0;
}

Output:

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed (neither the const nor the non-const versions modify the container).
The reference returned can be used to access or modify characters. Concurrently accessing or modifying different characters is safe.

Exception safety

If the basic_string is not empty, the function never throws exceptions (no-throw guarantee).
Otherwise, it causes undefined behavior.