NSInteger 1 when multiplied by 0.05f returns 0.0500000007

Question

A float problem in iOS when indexPath.row=1

Float32 value=0.05*indexPath.row;

it returns value=0.0500000007 but it should be 0.05. How to fix this??

http://www.exploringbinary.com/floating-point-questions-are-endless-on-stackoverflow-com/ — trojanfoe, Jul 15 '14 at 10:17
possible duplicate of [Is floating point math broken?](http://stackoverflow.com/questions/588004/is-floating-point-math-broken) — Pascal Cuoq, Jul 15 '14 at 12:05
The closest IEEE 754 32-bit binary floating point number to 0.05 is 0.0500000007450580596923828125. Multiplying it by 1 is not going to change its value. — Patricia Shanahan, Jul 15 '14 at 13:01
@trojanfoe thanks that really helped! esp. http://www.exploringbinary.com/why-0-point-1-does-not-exist-in-floating-point/ — sargeras, Jul 16 '14 at 08:51

score 3 · Accepted Answer · answered Jul 15 '14 at 10:15

3

Welcome to floating point errors.

The easiest way to fix this is just to round the number after multiplying.

You can read more about why this is happening on this random website I found on Google.

answered Jul 15 '14 at 10:15

Fogmeister

1

thanks... even after rounding the float It was still saving 0.0500000007 but i ended up changing the way i needed... – sargeras Jul 16 '14 at 08:54

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