关于Scala Double数据类型精度

Question

I'm fairly a newbie to scala and in my baby steps, i'm using Centso 7.2 and Scala 2.12 with sbt console: here is my question is:

scala> val Y=5.12345938988398773983748934789473289472384723984723849
Y: Double = 5.123459389883988

This is with 15 precision and giving the value as excpected

and

scala> val u=4.91839028309283892389012
u: Double = 4.9183902830928385

This is supposed to be 4.9183902830928 390 ---> may be I'm missing something if not then it is loosing the precision value.

Can you please help me understand how Scala is treating this causing this precision inconsistency.

Answer 1

As you probably know, computers store numbers not in decimal but in binary format. And when it comes to floating point numbers they use IEEE 754 standard .

Here you can find a great explanation and examples of how computer converts floating point numbers to and from IEEE 754 format.