btw, thanks for your response. I'm not sure as if I understand why. It's not like I'm using a very precise number when dealing with the hundreths place.
Even without the multiplication the number gets messed up. eg. $a = 17.00; $a+= 1.10; $a+= 0.32; $a+= 0.07; print $a."<br>"; // 18.49 var_dump($a); // float(18.49) var_dump($a-18.49); // float(3.5527136788005E-15) I'm just trying to add money amounts? Can I not rely on floats to do this? Richard Lynch wrote: > Floats are NEVER going to be coming out "even" reliably. > > You'll have to check if the difference is less than X for whatever number > X you like. > > Or you can look at something like BC_MATH where precision can be carried > out as far as you like... > > But what you are seeing is to be expected. > > That's just the way computers work, basically. > > On Mon, April 4, 2005 5:07 pm, Anthony Tippett said: > >>Ok i've narrowed it down a little bit but still can't figure it out.. >> >>Here's the code and what I get for the output. Does anyone know what's >>going on? Can someone else run it on their computer and see if they get >>the same results? >><?php >> >>$a = "17.00" * "1"; >>$a+= "1.10" * "1"; >>$a+= "0.32" * "1"; >>$a+= "0.07" * "1"; >> >>print $a."<br>"; // 18.49 >> >>var_dump($a); // float(18.49) >>var_dump($a-18.49); // float(3.5527136788005E-15) >>?> >> >> >>Anthony Tippett wrote: >> >>>I'm having trouble figuring out why subtraction of two floats are giving >>>me a very small number. I'm thinking it has something to do with the >>>internals of type casting, but i'm not sure. If anyone has seen this or >>>can give me some suggestions, please. >>> >>>I have 2 variables that go through a while loop and are >>>added/subtracted/ multipled. InvAmt and InvPay are shown as >>>floats but when they are subtracted, they give me a really small >>>number >>> >>>// code >>>var_dump($InvAmt); >>>var_dump($InvPay); >>>var_dump($InvAmt-$InvPay); >>> >>>// output >>>float(18.49) >>>float(18.49) >>>float(2.1316282072803E-14) >>> >> >>-- >>PHP General Mailing List (http://www.php.net/) >>To unsubscribe, visit: http://www.php.net/unsub.php >> >> > > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
