How to avoid floating point precision errors with floats or doubles in Java? [duplicate]

There is a no exact representation of 0.1 as a float or double. Because of this representation error the results are slightly different from what you expected.

A couple of approaches you can use:

  • When using the double type, only display as many digits as you need. When checking for equality allow for a small tolerance either way.
  • Alternatively use a type that allows you to store the numbers you are trying to represent exactly, for example BigDecimal can represent 0.1 exactly.

Example code for BigDecimal:

BigDecimal step = new BigDecimal("0.1");
for (BigDecimal value = BigDecimal.ZERO;
     value.compareTo(BigDecimal.ONE) < 0;
     value = value.add(step)) {

See it online: ideone

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