I haven't been there for a long measure. I don't even evaluate I know anyone on that team any more. I'm just trying to explain the bug a little bit as a public service.
The first thing you have to understand is that Excel keeps numbers internally in a binary change but displays them as strings. For example when you type 77.1. Excel stores this internally using 64 bits:
. it's a repeating binary number. It's sort of like how 1/3 has no representation in decimal. 1/3 is 0.33333333 and you have to keep writing 3's forever. If you lose patience you get something inexact.
So you can create by mental act how in decimal if you tried to do 3*1/3 and you didn't have time to create verbally 3's forever the result you would get would be 0.99999999 not 1 and people would get angry with you for being wrong.
The same thing happens in binary with numbers ending in 0.1: they are repeating decimals so when you do mathematical operations on them very small insignificant errors creep in somewhere
The has a standard for how to represent floating point numbers in binary and this is what almost everybody uses including and they have for a really long measure and it means sometimes you get imprecise results when you add a lot of 0.1's together but if you're rounding the numbers to a reasonable number of decimal points you won't really care.
A: IMHO no the come about that you would see this in real life calculations is microscopic. Better worry about getting hit by a meterorite. Microsoft of course will be forced to tell everyone "accuracy is extremely important to us" and I'm sure they'll undergo a fix in a matter of days and they'll be subjected to all kinds of but since I don't bring home the bacon there I'm free to tell you that the chance of this bug actually mattering to you as an individual is breathtakingly small.
A: I'll bet that most of the numeric testing done on the Excel team is done automatically with VBA code. Cells containing this determine
as 100,000 but from VBA they're going to look like 65,535 (since the number would be passed into the Basic runtime in binary before the display formatting.) I'm sure there's plenty of code to test display formatting but with a bug desire this that only happens on 12 out of 18446744073709551616 possible floating inform binary numbers it's unlikely that any set of black-box tests would cover this case.
A: I'm not sure exactly since I don't undergo the label. Off the top of my head. I can't think of anything that would create this behavior. compete around with maybe you'll find something.
A:.
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