You may have been dismayed by the lack of error checking and error handling in the Explorations so far. That’s about to change. C++, like most modern programming languages, supports exceptions as a way to jump out of the normal flow of control in response to an error or other exceptional condition. This Exploration introduces exceptions: how to throw them, how to catch them, when the language and library use them, and when and how you should use them.
Exploration 9 introduced vector’s at member function, which retrieves a vector element at a particular index. At the time, I wrote that most programs ...