java division and decimal error

[heartysnowy]

Hi everyone,

i had a problem with my calculation..below is a sample of my code

double ggg = 170000.0 * (1.0 + (10.0/100) );
System.out.println("total :" + ggg );

i was trying to calculate the certain percentage based on the user input value but I got this kind of weird math error...
the expected result should b total : 187,000.0
but the actual result is total : 187,000.00000000003 <----

can help me explain why there is a decimal value is involved?? and how shall I get rid of it ?
Thanks in advance :)

[PhHein]

Using Variable Argument Lists and Some Things You Should Know About Floating-Point Arithmetic
What Every Computer Scientist Should Know About Floating-Point Arithmetic
Floating Point : Java Glossary

[masijade]

Floating-point arithmetic - JavaWorld

Edit: Far too slow and far too little (too little too late). ;-)

[heartysnowy]

thanks for the links

ok since that's a binary error, i assume that nothing can be done to solve it....
would it be save to trim them off by using Decimalformat?

[dlorde]

You could also use BigDecimal to round it to the number of places you want.

[xcallmejudasx]

Well that depends on what your code is being used for. If it's just some simple calculator for class or being used in some non crucial field(ie !banks, accouting, medicine, professional software) then yes it should be fine.

However if this is going to be used some place where fractions of a cent add up then yes it is important(look at office space and how a fraction of a cent ended up)