On 13 November 2017 at 11:42, Andrew Haley wrote: > On 13/11/17 10:38, Mason wrote: >> On 09/11/2017 16:46, Vincent Lefevre wrote: >> >>> Actually, that's mainly a language design bug, which doesn't show >>> the error for 460 (which is representable exactly). >> >> It's not clear to me exactly /what/ you are calling a language design bug? >> And in what language? C? IEEE 754?> (AFAIK, C is pretty loose with the floating point spec.) > > This is C++. The problem is that std::cout << v doesn't print all of > the digits in v: ideally, it'd print the minimum number of digits such > that reading the number back would result in a double equal to v. It might be nice to have that as an option (maybe via an I/O manipulator like std::fixed) but even if it wasn't too late to change the default behaviour, most people probably want 1.1 to be printed as 1.1 even though it's really something different.
