• korstmos@kbin.social
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      1 year ago

      Because even a long (64-bit int) is too small :)
      A long can hold 2^64-1 = 1.84E19
      A double can hold 1.79E308

      Double does some black magic with an exponent, and can hold absolutely massive numbers!

      Double also has some situations that it defines as “infinity”, a concept that does not exist in long as far as I know (?)

    • whats_a_refoogee@sh.itjust.works
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      1 year ago

      To avoid a type conversion that might not be expected. Integer math in Java differs from floating point math.

      Math.floor(10.6) / Math.floor(4.6) = 2.5 (double)

      If floor returned a long, then

      Math.floor(10.6) / Math.floor(4.6) = 2 (long)

      If your entire code section is working with doubles, you might not like finding Math.floor() unexpectedly creating a condition for integer division and messing up your calculation. (Have fun debugging this if you’re not actively aware of this behavior).