Bug #17630: '+' doesn't work correctly for some floats (x.07 + y.4 will give z.46999999999997 instead of z.47)

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: 2.7.2p137
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN

[zGalili (Ziv Galili)]

1.02 + 1.4 will give 2.42 as expected

but not for all cases.

examples for wrong answers:

1.07 + 1.4
-> 2.4699999999999998
255.07 + 5.4
-> 260.46999999999997
480.07 + 5.4
-> 485.46999999999997

other numbers works correctly:

255.06 + 5.5
-> 260.56
2.07 + 222222.4
-> 222224.47

seems like the problem is with x.07 + y.4 but only for some results.

[chrisseaton (Chris Seaton)]

Did you read this?

https://bugs.ruby-lang.org/#Floating-point-numbers

[ufuk (Ufuk Kayserilioglu)]

You might also want to take a look at this: https://0.30000000000000004.com/

[mame (Yusuke Endoh)]

• Status changed from Open to Rejected

As they say, this is by design. Closing.