std::basic_string<CharT,Traits,Allocator>::at - cppreference.com (original) (raw)

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 invalid access.

Contents

• 1 Parameters
• 2 Return value
• 3 Exceptions
• 4 Complexity
• 5 Example
• 6 Defect reports
• 7 See also

[edit] Parameters

[edit] Return value

Reference to the requested character.

[edit] 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).

[edit] Complexity

Constant.

[edit] Example

#include #include #include   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

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also

| | accesses the specified character (public member function) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | accesses the specified character with bounds checking (public member function of std::basic_string_view<CharT,Traits>) [edit] |