Hi all I've just finished this kind of calculator and I would like to hear a little feed back on it, I tried to use a little bit of all the stuff I've been researching in the last couple weeks. I would just like to know if I seem to be going in the right direction or if there is something i'm doing that is bad practice.
Hmm, so far it looks like you're going on a good track. Out of curiosity, is this an assignment for a class or something you're doing on your own?
Edit: You can save yourself a bit of headache with the choice == 'lowercase' || choice == 'UPPERCASE' statements by including <cctype> and using either std::toupper(char) or std::tolower(char) to uppercase or lowercase a character, respectively.
Doubles don't really have a problem with overflows, however. There is no real need to put in a set for that, because all that will happen is that you will print "inf" (infinity) instead of the value that you expected (e.g. 5.614e+613). The same goes for dividing by 0 with a double, you get "inf" as the result.