https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64677
--- Comment #10 from Mikhail Maltsev <maltsevm at gmail dot com> --- > 1. Why does the answer change based on the -std? I could reproduce the same result on GCC 4.8.2. I suppose that the most significant difference is that C++11 supports constexpr (and std::complex has constexpr constructor). Also, at higher optimization level, e.g. -O3, C++98 version will also get folded (it just requires more inlining than C++11). > Is Wolfram Alpha considered the authoritative answer? It's unlikely that it will give incorrect answer, but of course is cannot be considered a reference implementation, like, for example the C++ standard. By the way, according to C++ standard, precision of floating point numbers is implementation-defined.
