From cppreference.com
CharT&back(); (1)(constexpr since C++20)constCharT&back()const; (2)(constexpr since C++20)Returns reference to the last character in the string.
If
is true, the behavior is undefined.
(until C++26)If
is true:
If the implementation is
, a
occurs.
If the implementation is not hardened, the behavior is undefined.
(since C++26)Return value
operator[](size()-1)
Complexity
Constant.
Notes
In libstdc++, back() is
in C++98 mode.
Example
Run this code
#include<iostream>#include<string>intmain(){std::strings("Exemplary");char&back1=s.back();back1='s';std::cout<<s<<'\n';// "Exemplars"std::stringconstc("Exemplary");charconst&back2=c.back();std::cout<<back2<<'\n';// 'y'}Output:
Exemplars y Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
C++98
did not have the member function back()added See also
(DR*)
accesses the first character
(public member function)
accesses the last character
(public member function of std::basic_string_view<CharT,Traits>)