number problems

[gazza]

I run a few erro checks on my site and one of them seems to have hit a brick wall...

if (29.9+0.49==30.39) {
echo "1";
} else {
echo "0";
}

this always prints 0

Can anyone explain why and what i need to do with 29.9 to get it to print 1 ...

I've tried round,2 and also tries settype to double...

The fundamental problem lies in the fact that

echo 29.9+0.49-30.39;
prints -3.5527136788005E-15

but
echo 29.91+0.49-30.40;
prints 0;

Any ideas .. problem seems to be the 29.9

Thanks
Gary

[dalecosp]

$t=number_format((29.9+0.49),2);

if ($t==30.39) {
   echo "yup!";
}

This works. I guess [man]number_format/man is really for printing numbers, but it addresses whatever complex binary issue this is (I have a rather unmathematical brain, myself...) 🙂

Did you try "29.90+0.49"?