std::string front() method

since C++20

// Non const versionconstexpr CharT& front();// Const versionconstexpr const CharT& front() const;

since C++11

// Non const versionCharT& front();// Const versionconst CharT& front() const;

Returns a reference

to the first character in the string.

Undefined Behavior

Calling front() on an empty string is undefined behavior

.

Parameters

(none)

Return value

Reference to the first character.

Complexity

Constant - O(1).

Notes

For a string str, the expression str.front() is equivalent to *str.begin() and str[0].

Example

Main.cpp

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

Output

exemplaryExemplary