How do I correctly cite the C++ standard or its drafts?
I would cite the current version of C++ standard, based on the APA Style (6th edition), in particular, based on the APA guidelines for citing electronic sources (Web publications), as follows:

ISO/IEC. (2014). ISO International Standard ISO/IEC 14882:2014(E) – Programming Language C++. [Working draft]. Geneva, Switzerland: International Organization for Standardization (ISO). Retrieved from https://isocpp.org/std/the-standard

NOTE: When the current standard will be finalized and published, the citation will have to be updated accordingly by removing "[Working draft.]" phrase and updating the year (i.e., 2015).