tzippy - 9 months ago 40

Java Question

Comparing those two values shall result in a "true":

`53.9173333333333 53.9173`

Answer Source

If you want `a = 1.00001`

and `b = 0.99999`

be identified as equal:

```
return Math.abs(a - b) < 1e-4;
```

Otherwise, if you want `a = 1.00010`

and `b = 1.00019`

be identified as equal, and both `a`

and `b`

are positive and not huge:

```
return Math.floor(a * 10000) == Math.floor(b * 10000);
// compare by == is fine here because both sides are integral values.
// double can represent integral values below 2**53 exactly.
```

Otherwise, use the `truncate`

method as shown in http://stackoverflow.com/questions/1976809/are-there-any-functions-for-truncating-a-double-in-java:

```
BigDecimal aa = new BigDecimal(a);
BigDecimal bb = new BigDecimal(b);
aa = aa.setScale(4, BigDecimal.ROUND_DOWN);
bb = bb.setScale(4, BigDecimal.ROUND_DOWN);
return aa.equals(bb);
```