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std::basic_string::at(3) C++ Standard Libary std::basic_string::at(3) NAME std::basic_string::at - std::basic_string::at Synopsis CharT& at( size_type pos ); (1) (constexpr since C++20) const CharT& at( size_type pos ) const; (2) (constexpr since C++20) Returns a reference to the character at specified location pos. Bounds checking is performed, exception of type std::out_of_range will be thrown on in- valid access. Parameters pos - position of the character to return Return value Reference to the requested character. Exceptions Throws std::out_of_range if pos >= size(). If an exception is thrown for any reason, these functions have no effect (strong exception safety guarantee). Complexity Constant. Example // Run this code #include <iostream> #include <stdexcept> #include <string> int main() { std::string s("message"); // for capacity s = "abc"; s.at(2) = 'x'; // OK std::cout << s << '\n'; std::cout << "string size = " << s.size() << '\n'; std::cout << "string capacity = " << s.capacity() << '\n'; try { // This will throw since the requested offset is greater than the current size. s.at(3) = 'x'; } catch (std::out_of_range const& exc) { std::cout << exc.what() << '\n'; } } Possible output: abx string size = 3 string capacity = 7 basic_string::at Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Correct behavior LWG 847 C++98 there was no exception safety added strong exception safety guarantee guarantee See also operator[] accesses the specified character (public member function) at accesses the specified character with bounds checking (public member function of std::ba- sic_string_view<CharT,Traits>) http://cppreference.com 2024.06.10 std::basic_string::at(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Complexity | Example | Possible output: | See also
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