Java doesn't know how to multiply? What?

Question

So I'm making a cookie clicker clone in java (shame on me) and for one thing, I need the double to increase by .1 for each cursor you own. The code looks like this (cookies is a double, and all other values are ints):

cookies = cookies + (cursors*.1+grandmas/2+farms*4+factories*10);

however, when this outputs, it outputs numbers like 2.399999999999999 instead of 2.4. What is going on?

Try `cursors/10.0` instead of `cursors*0.1` This will reduce the error. — Peter Lawrey, May 06 '14 at 17:13
And it has *nothing* to do with java. This is *general* behavior for all languages that use IEEE floating point math. Because thats how IEEE math *works*, be it C/C++/Java/.net whatever. — Durandal, May 06 '14 at 17:38

score 0 · Accepted Answer · answered May 06 '14 at 17:15

0

That is double's precision. You could use

cookies = Math.round( cookies * 100.0 ) / 100.0;

answered May 06 '14 at 17:15

Syam S

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Java doesn't know how to multiply? What?

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