std::basic_string_view::operator[]

constexpr const_reference operator[](size_type pos) const;		(since C++17)

Returns a const reference to the character at specified location pos.

No bounds checking is performed: the behavior is undefined if pos >= size().

Parameters

pos

-

position of the character to return

Return value

Const reference to the requested character

Exceptions

Does not throw

Complexity

Constant.

Notes

Unlike std::basic_string::operator[], std::basic_string_view::operator[](size()) has undefined behavior instead of returning CharT().

Example

Run this code

#include <iostream>
#include <string_view>
int main()
{
    std::string str = "Exemplar";
    std::string_view v = str;
    std::cout << v[2] << '\n';
//  v[2] = 'y'; // Error: cannot modify through a string view
    str[2] = 'y';
    std::cout << v[2] << '\n';
}

Output:

e
y

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

Null-terminated strings
Byte strings
Multibyte strings
Wide strings
Classes
basic_string
basic_string_view (C++17)
char_traits