My pet peeves, which most programmers find unimportant but which I personally find to hurt readability a lot, is that VC++ is unable to compile the following C++ code:
bool result = true and not false;
… because VC++ doesn’t recognize and, or and not (along with the rest of ISO 646) as valid tokens.
Clarification: The standard mentions the treatment of the above tokens in §2.12, marks them as reserved in §2.11 and defines an equivalence mapping for them in §2.5 to the more conventional operator representations (e.g. and corresponds to &&). It isn’t clear why they get a special status next to the other keywords. Even more confusingly, appendix C2.2 suddenly calls them “keywords”. Still, the standard is absolutely clear about their treatment and semantics. VC simply doesn’t implement these paragraphs (unless you specify the /Za flag during compilation).
