floating point subtraction error

[compgeek83]

$balance_due = $salesreceipt_grandtotal - $payments_applied;

if $balance_due is 0 I get "5.6843418860808E-14" instead of 0.  What can I do to return 0 instead of this error?

[Irate]

Not using floats but integers helps.

 

This is not a problem specific to PHP, by the way.

 

Try using this instead.

 

$balance_due = (int) $salesreceipt_grandtotal - $payments_applied;

[compgeek83]

that helped in a way, now I get "-0.64999999999998" instead of the error, if I echo out each variable they are identical though

[Irate]

The result you got in the first version is not an error, 5.6843418860808E-14 actually equals -0.64999999999998, it's just written in its exponential form.

 

Try using the (int) statement twice, like this.

 

$balance_due = ((int) $salesreceipt_grandtotal) - ((int) $payments_applied);

[compgeek83]

Bingo, that works perfectly, thank you!

[Irate]

Bingo, that works perfectly, thank you!

 

You're welcome.

 

Also, I noticed that 5.68...E-14 is not -0.649..., I forgot that in the first code I provided, one of the results was already being converted to an int.

So, for the record, 5.68...E-14 is close to -0.649..., but not equal to it.

 

Sorry for the confusion.