3228: Day Counter

2026-04-03T13:58:57Z

2A02:3100:B3AA:B300:8DDB:3FDA:A56B:264: 2^-31 isn't even an integer

{{comic
| number = 3228
| date = April 3, 2026
| title = Day Counter
| image = day_counter_2x.png
| imagesize = 319x287px
| noexpand = true
| titletext = It has been −2,147,483,648 days since our last integer overflow.
}}

==Explanation==
{{incomplete|This page was created -.000000000000000032 days ago. Don't remove this notice too soon.}}
{{w|Floating-point arithmetic|Floating point numbers}} are numbers stored in a computer as {{w|Scientific Notation}}, rounded to fit. They are often used for decimal numbers, where storing the full number with all decimal places would result in using much space. However, the rounding required to use these numbers can result in rounding errors, which can cause a fair amount of trouble, especially when comparing them or printing them to a screen in a human readable format.

This is shown in the comic, where a counter is shown of days since there was last a floating point error. However, the amount of time has been changed from a floating point & back, creating the ridiculous illusion that -0.00000000000000044 days have passed, which implies a 'negative' number of days, which is impossible{{cn}}. It also, even if it was a positive number, would mean less than a microsecond had passed since the last error, which would be an unfeasably short amount of time. Of course, the joke is that in making the sign showing the amount of time since a floating point error was last made, they are creating a floating point error, meaning the sign is invalid. Also, if they tried to reset the sign, they might make the same error again, repeating the cycle over & over, which would not be ideal.

Coincidentally enough, [[Cueball]] is also floating - off his seat in this case. The seat itself looks the same as the chair in [[2144]], possibly meaning making people levitate is one of it's numerous settings.

Floating point errors are particularly common in programming, specially in languages that implicitly convert decimal numbers to binary floating point, so an approximation is already made at conversion leading to unexpected results. The title text cites another common programming problem, integer overflow. When a value gets bigger than the biggest integer that can be represented in a certain format, it "warps around" to the smallest value. In case of 32-bit signed integers this value is -2^31, that is −2,147,483,648.

The dropdown menu beneath the comic allows the user to select different "modes". These include the typical "Light mode" and "Dark mode", but also includes some atypical modes such as "Dorian Greyscale Mode" which gradually turns the page darker shades of grey to simulate aging as in the 1890 Oscar Wilde story "The Picture of Dorian Gray".

==Transcript==
[White Hat, Ponytail, Cueball, and Megan are all below a large sign. White Hat and Ponytail appear to be discussing something, while Cueball is sitting at his desk working on a laptop and Megan is walking away. The sign has text on it, as well as a large display presumably meant to show a number.]

:[Sign:] It has been
:[Display:] -0.00000000000000044
:[Sign:] days since our last floating point error

{{comic discussion}}<noinclude>[[Category:Interactive comics]][[Category:Dynamic comics]]

explain xkcd - User contributions [en]

3228: Day Counter