Comment on IEEE 754

• wewbull@feddit.uk ⁨1⁩ ⁨year⁩ ago

  Knowing not to use floating point with money is good use of that knowledge.

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• psivchaz@reddthat.com ⁨1⁩ ⁨year⁩ ago

  You’d be dismayed to find out how often I’ve seen people do that.

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• zqwzzle@lemmy.ca ⁨1⁩ ⁨year⁩ ago

  Yeah I shudder when I see floats and currency.

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  • Womble@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Eh, if you use doubles and you add 0.000314 (just over 0.03 cents) to ten billion dollars you have an error of 1/1000 of a cent, and thats a deliberately perverse transaction. Its not ideal but its not the waiting disaster that using single precision is.

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  • SubArcticTundra@lemmy.ml ⁨1⁩ ⁨year⁩ ago

    That sounds like an accident waiting to happen

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• Saleh@feddit.org ⁨1⁩ ⁨year⁩ ago

  How do you do money? Especially with stuff like some prices having three or four decimals

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  • jmcs@discuss.tchncs.de ⁨1⁩ ⁨year⁩ ago

    Instead of representing $1.102 as 1.102 your store it as 1012 (or whatever precision you need) and divide by 1000 only for displaying it.

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    • Saleh@feddit.org ⁨1⁩ ⁨year⁩ ago

      So if you handle different precisions you also need to store the precision/exponent explicitly for every value. Or would you sanitise this at input and throw an exception if someone wants more precision than the program is made for?

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      • wewbull@feddit.uk ⁨1⁩ ⁨year⁩ ago

        No exponent, or at least a common fixed exponent. The technique is called “fixed point” as opposed to “floating point”. The rationale is always to have a known level of precision.

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      • jmcs@discuss.tchncs.de ⁨1⁩ ⁨year⁩ ago

        It depends on the requirements of your app and what programming language you use. Sometimes you can get away with using a fixed precision that you can assume everywhere, but most common programming languages will have some implementation of a decimal type with variable precision if needed, so you won’t need to implement it on your own outside of university exercises.

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