std::basic_string_view<CharT,Traits>::at
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std::basic_string_view
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(C++20)
(C++23)
basic_string_view::at
Constants
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Deduction guides (C++20)
constexpr const_reference at( size_type pos ) const;
(since C++17)
Returns a const reference to the character at specified location pos. Bounds checking is performed, exception of type std::out_of_range will be thrown on invalid access.
[edit] Parameters
pos
-
position of the character to return
[edit] Return value
Const reference to the requested character.
[edit] Exceptions
Throws std::out_of_range if pos >= size().
[edit] Complexity
Constant.
[edit] Example
Run this code
#include <iostream> #include <stdexcept> #include <string_view> int main() { std::string_view str_view("abcdef"); try { for (std::size_t i = 0; true; ++i) std::cout << i << ": " << str_view.at(i) << '\n'; } catch (const std::out_of_range & e) { std::cout << "Whooops. Index is out of range.\n"; std::cout << e.what() << '\n'; } }
Possible output:
0: a 1: b 2: c 3: d 4: e 5: f 6: Whooops. Index is out of range. basic_string_view::at: __pos (which is 6) >= this->size() (which is 6)