Namespaces
Variants
Views
Actions

std::basic_string<CharT,Traits,Allocator>::front

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
 
CharT& front();
(1) (constexpr since C++20)
const CharT& front() const;
(2) (constexpr since C++20)

Returns reference to the first character in the string. The behavior is undefined if empty() is true.

Contents

[edit] Parameters

(none)

[edit] Return value

Reference to the first character, equivalent to operator[](0).

[edit] Complexity

Constant.

[edit] Notes

In libstdc++, front() is not available in C++98 mode.

[edit] Example

#include <iostream>
#include <string>
 
int main()
{
    std::string s("Exemplary");
    char& f1 = s.front();
    f1 = 'e';
    std::cout << s << '\n'; // "exemplary"
 
    std::string const c("Exemplary");
    char const& f2 = c.front();
    std::cout << &f2 << '\n'; // "Exemplary"
}

Output:

exemplary
Exemplary

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 534 C++98 std::basic_string did not have the member function front() added

[edit] See also

(DR*)
accesses the last character
(public member function) [edit]
accesses the first character
(public member function of std::basic_string_view<CharT,Traits>) [edit]