Unexpected result in Java (floating to integer)

Question

I have a problem with this

System.out.print((9/5) * 3);

I expects the result 5.4 but it returns 3. Why is this happening?

all 3 numbers are integers so you get an integer as a result. — OH GOD SPIDERS, Jun 08 '17 at 12:13

score 8 · Accepted Answer · answered Jun 08 '17 at 12:14

8

9/5 is evaluated in integer arithmetic, so it's equal to 1.

Writing 9.0 / 5 * 3 is a common fix. (Promoting one of the coefficients in the term to a double forces the evaluation to take place in double precision floating point.)

answered Jun 08 '17 at 12:14

Bathsheba

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score 1 · Answer 2 · answered Jun 08 '17 at 12:14

1

System.out.print((9.0/5) * 3);

answered Jun 08 '17 at 12:14

Ramesh Khadka

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Adding some more explanation would be better. :) – Sanket Makani Jun 08 '17 at 12:17

score 1 · Answer 3 · answered Jun 08 '17 at 12:21

In java when you make division of integers it will return an integer not a real number :

9/5 return 1 instead of 1.8

to solve your problem you have two solutions :

use a real number instead so you have to use 9.0/5
or you can cast the number to double ((double)9/5) * 3

score 1 · Answer 4 · answered Jun 08 '17 at 12:28

1

All the numbers are integer there so it will give integer result you may make 9.0 or 5.0 to get that answer... As given below..

System.out.print((9.0/5) * 3); OR
System.out.print((9/5.0) * 3);

answered Jun 08 '17 at 12:28

Vikas Suryawanshi

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I'd be inclined to remove the redundant parentheses since (i) I'm dogmatic about that, and (ii) you are vulnerable to someone refactoring to `(9 / 5) * 3.0`. But have an upvote all the same. – Bathsheba Jun 08 '17 at 12:32

Unexpected result in Java (floating to integer)

4 Answers4