Lost data when divide float by 1000

Question

I hava float

float data = 24931192;

When i divide it by 1000

data = data / 1000;

it return for me 24931.191. Can anyone tell me why? and how can i prevent it? Thank you

Answer 1

Floats/floating point numbers only have so much precision (23 bits of precision in Java, to be precise), and you just ran into an issue where that precision isn't quite enough. Try using doubles if floats aren't enough, though even those will run into issues eventually.

Answer 2

Floats have limited precision. Here you can read more about how floats are encoded: http://en.wikipedia.org/wiki/IEEE_floating-point_standard

If you care about precision you should use BigDecimal: http://docs.oracle.com/javase/1.5.0/docs/api/java/math/BigDecimal.html