From cppreference.com
CharT&front(); (1)(constexpr since C++20)constCharT&front()const; (2)(constexpr since C++20)Returns reference to the first 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[](0)
Complexity
Constant.
Notes
In libstdc++, front() is
in C++98 mode.
Example
Run this code
#include<iostream>#include<string>intmain(){std::strings("Exemplary");char&f1=s.front();f1='e';std::cout<<s<<'\n';// "exemplary"std::stringconstc("Exemplary");charconst&f2=c.front();std::cout<<&f2<<'\n';// "Exemplary"}Output:
exemplary Exemplary 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 front()added See also
(DR*)
accesses the last character
(public member function)
accesses the first character
(public member function of std::basic_string_view<CharT,Traits>)