Losing decimal places Java Double

Question

Using Java i am getting a weird result

Double width = super.getWidth()/(32);
System.out.println(super.getWidth() + "  " + width);

prints 312 9.0

312/32 should be 9.75?

You're doing integer division. Try `super.getWidth() / 32.0;` — Jesper, Feb 28 '14 at 15:20

score 4 · Accepted Answer · answered Feb 28 '14 at 15:21

Assuming that super.getWidth() returns an integral type (an int, a long, etc.) the precision is lost during the division. When you divide a value of an integral type by an int, only the integer portion of the result is kept, while the fractional part is discarded.

Divide by 32.0 to fix the problem:

double width = super.getWidth()/32.0;
System.out.println(super.getWidth() + "  " + width);

score 2 · Answer 2 · answered Feb 28 '14 at 15:22

2

You need

Double width = super.getWidth()/(32.0);

When the java compiler comes across your original code, it sees two integers, and returns an integer. This way, it sees an integer and a double, therefore returning a double.

answered Feb 28 '14 at 15:22

PlasmaPower

1,864
15
18

score 1 · Answer 3 · answered Feb 28 '14 at 15:20

1

Try

Double width = super.getWidth()/(32.0);
System.out.println(super.getWidth() + "  " + width);

answered Feb 28 '14 at 15:20

Hugo Sousa

1,904
2
15
28

1

You should "try" answering the question, not just providing a fixed code snippet without explaining or even highlighting the change ;) – hyde Feb 28 '14 at 15:33

Losing decimal places Java Double

3 Answers3