std::string back() method

since C++20

// Non const version
constexpr CharT& back();

// Const version
constexpr const CharT& back() const;

since C++11

// Non const version
CharT& back();

// Const version
const CharT& back() const;

Returns a reference

to the last character in the string.

Undefined Behavior

Calling back() on an empty string is undefined behavior

.

Parameters

(none)

Return value

Reference to the last character.

Complexity

Constant - O(1).

Notes

For a string str, the expression str.back() is equivalent to *std::prev(str.begin()) and str[str.size() - 1].

Example

Main.cpp

#include <iostream>
#include <string>
 
int main()
{
  {
    std::string s("Exemplary");
    char& back = s.back();
    back = 's';
    std::cout << s << '\n'; // "Exemplars"
  }
 
  {
    std::string const c("Exemplary");
    char const& back = c.back();
    std::cout << back << '\n'; // 'y'
  }
}

Output

Exemplars
y