Working with double

Question

Hello !
I'm working with double... doing substraction.
I'm using a JNI Timer class to get the current time with a better precision that the milliseconds for currentTimeMillis(), to calculate some average time passed in code.
My problem: for example, the operation :
1.123456789 - 1.123456777
does not return 0.000000012, but something like 1.2 for example...
Is this normal ?
How to get the real value without rounded ?
Thanks
Ludovic

Answer 1

How to get the real value without rounded ?Usually, the double precision is sufficient. But try this..
System.out.println(String.valueOf(1.123456789-1.123456777));//for reference
java.math.BigDecimal big1 = new java.math.BigDecimal("1.123456789");
java.math.BigDecimal big2 = new java.math.BigDecimal("1.123456777");
java.math.BigDecimal big3 = big1.subtract(big2);
System.out.println(String.valueOf(big3));