std::basic_string_view<CharT,Traits>::operator[] (3) - Linux Manuals

std::basic_string_view<CharT,Traits>::operator[]: std::basic_string_view<CharT,Traits>::operator[]

NAME

std::basic_string_view<CharT,Traits>::operator[] - std::basic_string_view<CharT,Traits>::operator[]

Synopsis

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