ID: 9411
Updated by: lyric
Old-Status: Closed
Status: Bogus
Old-Bug Type: *Regular Expressions
Bug Type: Math related
Assigned To: 

This is nothing to do with PHP, its just part of the way computers store 
floating-point numbers. It stores an aproximation of 0.32, as close as it can get, but 
when you start multiplying it, the little difference between 0.32 and what it stored 
starts to get magnified.

BTW, 5.5511151231258E-17 is 0.000000000000000055511151231258 which is *really* closed 
to 0.

If you want to output formatted numbers, you should either round it, or use printf()

Previous Comments:

[2001-02-22 16:05:47] [EMAIL PROTECTED]
This is normal floating point math behavior


[2001-02-22 15:45:55] [EMAIL PROTECTED]
Hi I am not sure if I have found a bug - what do you think.......?

Consider this:

$var1 = -0.32 + (0.1*3.2)

This should give var1 the value 0, instead it gives


Interestingly if you increase -0.33 and 3.3 respectively it gives the correct answer. 

Rob Burne



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