C++17 STL Cookbook

How it works...

We did some complex input retrieval in this section. The first noticeable thing is that we always did the retrieval and error checking at the same time.

The result of the expression cin >> x is again a reference to cin. This way, we can write cin >> x >> y >> z >> .... At the same time, it is possible to convert it into a Boolean value by using it in a Boolean context such as if conditions. The Boolean value tells us if the last read was successful. That is why we were able to write if (cin >> x >> y) {...}.

If we, for example, try to read an integer, but the input contains "foobar" as the next token, then parsing this into the integer is not possible and the stream object enters a fail state. This is only critical for the ...