CODEWITHSUNDEEP
visual-c++
jeninjames
jeninjames

Reputation: 128

floor() behave strangely VC++

I was doing some coding and suddenly wondered with a strange behavior of floor(). The piece of line that caused error is mentioned below:

printf("%f",floor(310.96*100));

and the output was 31095.0000.

Why is this happening?

Upvotes: 1

Views: 82

Answers (2)

Frank Bollack
Frank Bollack

Reputation: 25166

This is a typical floating point issue. The constant value 310.96 is not equally representable as a float number. Instead the closest float value representation is 310.9599914550781.

You can try out your self here. Multipled that by 100 and truncated with floor() results in your 31095.0000

Upvotes: 1

thumbmunkeys
thumbmunkeys

Reputation: 20764

Floating point numbers are not 100% exact 310.96*100 might result in 31095.99999999... hence your result, see also this

Upvotes: 0

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