I have noticed that printf performs an apparently inconsistent rounding of floating point values.
I divide a big number by 1000 and printf the resulting value with "%.1f". Here is the code: https://play.golang.org/p/e7dD3c6IHq2 I would expect the rounding rule to be "round away from zero" as defined here: https://math.stackexchange.com/a/2252888/33796 In this case 0.5 is rounded to 1 (or 0.05 to 0.1) and -0.5 to -1 (or -0.05 to -0.1). Here is what I see with golang 1.13.4: 999000/1000 = 999.0 999050/1000 = 999.0 // expected 999.1 999100/1000 = 999.1 999150/1000 = 999.1 // expected 999.2 999200/1000 = 999.2 999250/1000 = 999.2 // expected 999.3 999300/1000 = 999.3 999350/1000 = 999.4 999400/1000 = 999.4 999450/1000 = 999.5 999500/1000 = 999.5 999550/1000 = 999.5 // expected 999.6 999600/1000 = 999.6 999650/1000 = 999.6 // expected 999.7 999700/1000 = 999.7 999750/1000 = 999.8 999800/1000 = 999.8 999850/1000 = 999.9 999900/1000 = 999.9 999950/1000 = 1000.0 -999950/1000 = -1000.0 -999900/1000 = -999.9 -999850/1000 = -999.9 -999800/1000 = -999.8 -999750/1000 = -999.8 -999700/1000 = -999.7 -999650/1000 = -999.6 // expected -999.7 -999600/1000 = -999.6 -999550/1000 = -999.5 // expected -999.6 -999500/1000 = -999.5 -999450/1000 = -999.5 -999400/1000 = -999.4 -999350/1000 = -999.4 -999300/1000 = -999.3 -999250/1000 = -999.2 // expected -999.3 -999200/1000 = -999.2 -999150/1000 = -999.1 // expected -999.2 -999100/1000 = -999.1 -999050/1000 = -999.0 // expected -999.1 Is this actual rounding the result of a rule or is it pseudo random ? -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/7ace93da-e330-4069-9b0c-6d1aa15fc179%40googlegroups.com.
