Steven Schveighoffer wrote: > On Mon, 06 Apr 2009 08:36:18 -0400, Don <nos...@nospam.com> wrote: > >> Sam Hu wrote: >>> Thank you! >>> Anothe silly question then:What's the disadvantage to have the >>> built-in type of i-type? >>> Regards, >>> Sam >> >> It's a very nasty type. It supports *, but isn't closed under *. >> Which is really annoying for generic programming. >> >> idouble x = 2i; >> x *= x; // oops, this isn't imaginary. (BTW this currently compiles :o). > > This may be a dumb question, but aren't all real numbers also > technically imaginary numbers with a 0i term? that is, I would expect > the above to evaluate to: > > -4 + 0i > > Which I would view as an imaginary number. Am I completely wrong here?
You're thinking of "complex". -4 is real, 2i is imaginary, -4+2i is complex. Regarding Don's example, imaginary*imaginary always yields a real, real*imaginary always yields an imaginary. It's the only builtin type I know of that changes type under multiplication with itself. -- Daniel
