There's more...

Of course, we can handle out of bounds accesses, instead of letting the whole app crash. In order to handle it, we catch the exception, in case it was thrown by the at function. Catching such an exception is simple. We just surround the at call with a try block and define the error handling in a catch block.

try {
    std::cout << "Out of range element value: " 
              << v.at(container_size + 10) << '\n';
} catch (const std::out_of_range &e) {
     std::cout << "Ooops, out of range access detected: " 
               << e.what() << '\n';
}