Time's Up

2022-04-01

The "up by 0" is probably from the careless use of floating point comparisons and rounding off. The change is probably more than 0.0 but less than 0.5. In floating point, even if a difference should be zero, it usually is not exactly zero, so this code will often fail:

if(change > 0.0) printf("Up"); else if (change < 0.0) printf("Down"); else printf("No Change");

Even when the change was mathematically zero, rounding errors in the calculations will generally make it a tiny bit positive or negative so "Up" or "Down" will randomly come out when "No Change" was expected. One fix is to define a constant for how much difference from 0 will count as not zero, say tol = 0.01, and test it like this:

if(change > tol) printf("Up"); else if (change < -tol) printf("Down"); else printf("No Change");

In this case, tol is 0.5, and a more reliable way is to round 'change' to the nearest integer first, then test the rounded number. This ensures that "Up", "Down" or "No Change" case will always match the displayed change.

TheGreatLobachevsky · 2022-04-04

The iOS post reminded me of a recent exchange with someone regarding Headphone Safety notifications. This person was in the UK and was complaining about not being to turn them off in settings. I had shared screenshots with them how, but they sad it wasn't available where they lived. But they checked again, and lo and behold, they were able to. After a big of searching - it turned out that was an EU regulation, and now that the UK left the EU, he was able to turn off the notifications. We were very amused by this fact.

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