A couple weeks ago, we debugged a temperature sign displaying 119 °F degrees in the dead of winter. Turned out to be a variable out-of-bounds problem.

Above is another whacko temperature bug from Fail Blog.

I started mucking with this bug using the same logic. Since the correct value is probably around 23°F, and since 222°F  + 23°F looks dangerously close to 255, the magic roll-over (or roll-under) point of despair and destruction looks to be a prime suspect.

Flipping it around, 255°F - 222°F  = 33°F,  which is dangerously close to the freezing point of water (32°F).

And … 32°F is 0°C, which is another dangerous roll-under point for unsigned chars.

Finally, both the beyond-boiling temperature AND the “Alerts” box in the upper left corner are RED.  While the number of Alerts is zero, somewhere the software knows evilness has occurred.

This time you figure it out - what’s the exact cause of failure?

Related Posts:

Let’s Debug it: Snow That’s Hot to the Touch!
Bugs in Public - Errors in Software and in Common Sense