digitalmars.D.bugs - [Issue 9889] New: Incorrect rounding on floating value formatting
- d-bugmail puremagic.com (42/42) Apr 06 2013 http://d.puremagic.com/issues/show_bug.cgi?id=9889
http://d.puremagic.com/issues/show_bug.cgi?id=9889 Summary: Incorrect rounding on floating value formatting Product: D Version: D2 Platform: All OS/Version: Windows Status: NEW Keywords: wrong-code Severity: normal Priority: P2 Component: Phobos AssignedTo: nobody puremagic.com ReportedBy: verylonglogin.reg gmail.com 13:51:19 MSD --- `std.format.formatValue` uses C's `snprintf` which works this way in `snn.lib`: --- import std.string; void main() { assert(format("%.1f", 0.09) == "0.1"); // Failed, formatted as "0.0" assert(format("%.1f", -0.09) == "-0.1"); // Failed, formatted as "-0.0" assert(format("%.1f", 0.095) == "0.1"); // OK assert(format("%.1f", -0.095) == "-0.1"); // OK assert(format("%.1f", 0.094) == "0.1"); // Failed, formatted as "0.0" assert(format("%.1f", -0.094) == "-0.1"); // Failed, formatted as "-0.0" } --- Workaround: --- real preformatFloating(real n, ubyte digits) { immutable k = 10.0L ^^ digits; return round(n * k) / k; } void main() { assert(format("%.1f", preformatFloating(0.09, 1)) == "0.1"); } --- -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 06 2013